This image shows the larva and pupa of Chrysomya megacephala.
Image via sciencedaily

Chrysomya megacephala is a tremendously abundant species and is used as fish bait in northern and south-west India. It is known to breed in human faeces, decomposed meat and fish as well as in discarded organic materials, and thrives on corpses in many parts of the world. This fly therefore serves as a potential vector of many diseases due to its close association with human dwellings and is considered important in medical, veterinary and forensic sciences.

Post mortem interval (PMI) determination is useful in cases of homicide, suicide and accidental or unattended death because of natural causes. An important aspect of calculating the PMI is the accurate and quick identification of the dipteran fly collected from a crime scene.

When determining PMI, behavior and developmental times of the specie is essential. The most common way currently used to identify dipteran flies is to study the adult stage under a compound microscope. This requires that the larvae collected at the scene be reared to maturity. The fly can be identified in its young, larval form but if the critical characteristics are small or vary ever so slightly, misidentification is possible.

However, morphological identification of the fly can be difficult. But identifying them genetically, by encoding collected DNA sequences of mitochondrial cytochrome oxidase gene subunit I (mtCOI), is a much more precise method. Three forms of C. megacephala are recognized presently, those being the normal form (nf), the synanthropic derived form (sdf) and the recently reported feral derived form (fdf).

Nf is confined to forests of South Pacific Islands while the sdf form has spread around the world from Papua New Guinea. Fdf, found in the forests of the Himalaya, India is morphologically intermediate between normal and synanthropic derived forms. However, the occurrence of the synanthropic derived form of C. megacephala has not been documented in the State of Tamil Nadu, India.

In this context, a report for the first time for C. megacephala (sdf) from Royapuram fishing harbour, Chennai, Tamil Nadu, South East India is significant. A colony of C. megacephala was established from numerous second and third instar larvae collected from decaying fishes. The life expectancy of this fly is 40-45 days. Freshly emerged adults from pupae were identified through morphological and molecular studies.

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“The smell of death” has been puzzling researchers for more than a decade. Two papers sparked the scientific community’s efforts in 2004 — one from a research station in Tennessee titled “Body farm” that analyzed the gases released during the latter stages of decomposition, the other from Greece, that focused on the early stages of the macabre process.

The preliminary list of carbon-based compounds given off during decay that these papers put together has been added on extensively since then. However, there have been conflicting reports about which ones are emitted only by humans. And so, in 2010 the Belgian Disaster Victim Identification Team asked analytical chemist Eva Cuypers and her forensic toxicology lab at the University of Leuven in Belgium for to find the best way to train cadaver dogs to pick out human scents.

Cuypers’s graduate student Elien Rosier started by putting tissue samples and organs from six autopsied corpses in jars in a lab closet. The jars were closed using screw caps which let in some air. They had stoppered holes that allowed the team to periodically take samples of the gas build-up inside.

Other jars were set up with pig, mouse, mole, rabbit, turtle, frog, sturgeon and bird remains. Pig remains in particular have often been used in past decomposition studies because of their rare similarity to human bodies: They have the same microbes in their guts, the same percentage of body fat, and similar hair as people. But it was not clear whether the decomposition process was the same because the two species had never been studied under identical conditions.

Rosier sampled the gases released by all the jars, and compared them by species. It took a long 6 months of work, during which she identified 452 compounds that make up the rotting smell of cadavers. Her first try was with compounds containing sulfur, as they seemed to differentiate between the samples. They weren’t unique to humans however, or even present in all humans — and they weren’t very stable chemically, disappearing over time; so she looked to .

Esters are chemical compounds that are crucial in the formation of animal fats. She found that eight compounds distinguished pig and human remains from those of other animals, and five esters separated pigs from humans, PLOS ONE reports:

“The mixture of [these] compounds might be used in the future to more specifically train cadaver dogs,” Cuypers says.

“So far there [hasn’t been] any study based on monitoring human and pig carcasses under exactly the same conditions,” says Agapios Agapiou, an analytical chemist at the University of Cyprus in Nicosia who was not involved with the work. “But there are still many steps before creating a synthetic substance to train cadaver dogs.”

John Sagebiel, an analytical chemist at the University of Nevada, Reno, who was also uninvolved in the study. says relying solely on analytical chemistry to determine what cadaver dogs are sniffing out is too limited. It would be better to work with the dogs themselves to figure that out, he adds.

“I don’t think there’s one specific thing that says it’s human,” he says.

Arpad Vass — who is associated with the University of Tennessee, Knoxville, Body Farm and has compiled a list of compounds released by decomposing humans — points out that the use of specific tissues, as opposed to a whole body, and their isolation in jars means the researchers are looking at just a subset of the bacteria and other environmental factors that influence decomposition.

Cuypers says her team plans to address some of these shortfalls in future studies.

“The next step in our research is to see whether the same compounds are found in buried, full decomposing bodies in the field and to see whether dogs trained on the mixture respond more specific[ally] to human decomposing bodies.” If this cocktail passes muster, the find could pave the way for developing an electronic nose that can do what dogs do, she adds.

Government data paints a grim picture. 1,215 animals were killed in South Africa last year, a triple of the 448 recorded in 2011. Out of these, 827 victims were took down out of Kurger Park’s population of 9000 animals.

Hey dude, pull my horn.
Image via iworry.org

Confronted with the surge in poaching incidents, Kruger national park has the keepers on high alert, and rhino killings are treated like a crime scene and scoured by forensic experts.

The last victim in the Kruger National Park’s poaching business is a black rhino, killed under the light of the fool moon. The shot alerted park keepers that rushed to the scene and in the ensuing firefight, shot and killed one of the poachers while his accomplice ran away.

Four days later, investigators – with a group of journalists in tow – arrived to collect DNA and other evidence to help trace the weapon and prove the origin of the horn sawn off for sale overseas. The scene that media were invited to this month was a few hundred meters off a dirt road in the bush, and not far from a perimeter fence – a poaching “hot spot”.

A game ranger stands guard as police investigate the scene around the carcass of a black rhinoceros that had been shot by poachers in the Kruger National Park, in this picture taken August 4, 2015.
Image via yahoo

Most poachers come from neighboring Mozambique, the world’s poorest country, sharing a 350 km (210 mile) wide border with Kruger, and from the small villages that surround the Park. The largest part of killings take place in the marginal areas of the park, and it makes sense – given the economic hardships of life around Kruger.

The forensic work was undertaken by police surgeon Silence Mdluli, who wore a face mask and was clad in blue surgical overalls, and investigator Bella Khosa.

The rotting corpse lay sprawled on its left side, its ribs picked clean by scavengers. The horn had been hacked off.

The forensic team’s work included taking tissue samples and cutting away a toenail for DNA analysis.

“If we recover the horn, this can be matched to the DNA,” Khosa explained.

The corpse was marked as exhibit A, while a pair of shell casings found about 10 m away were marked as exhibits “2” and “3”. They have been discharged from a .458 caliber rile – basically, an elephant gun. If it is ever retrieved, the shells could be matched to it. A metal detector was also used to locate any bullets still lodged in the corpse, but none were found. Given the high powered weapon use and the size of the animal (Black rhinos are the rarer and smaller of Africa’s two species – the other being the white rhino ) of around 200 kg (440 lb), investigators believe the slugs went right through it.

Mdluli also tied a plastic ribbon to the branch of a tree. “If a chopper sees the carcass, this will tell them it is a known crime scene,” he said.

Such investigations, combined with red-handed arrests made by rangers, are starting to yield results. In Mpumalanga province which borders Kruger, the conviction rate in rhino cases is currently 100 percent.

1. Networks: Anyone who knows anything about computer forensics knows investigators will look for clues on the computer. Usually they will go through an outside source, which specializes in . If people think about information on the network, they usually think in terms of data on servers or browser history. Some will think about browser cache. But one of the best sources of information can be the network itself. At its simplest, data gathering might involve logging the origin and destination of every information packet on the local network. A more involved example would be a proxy server – computer positioned between (or on) the gateway router between the local network and the internet. It could log all traffic, and might even perform analysis to find out what is in the packets going from the local network to the internet.

2. Smart Phones: A basic feature phone can provide information like where the owner has been and where he spends time using the GPS data it provides the carrier and records of text messages. The forensic possibilities of a smart phone are much greater. The smart phone is a very powerful computer. It probably has personal information, maybe even financial information on it. Pictures, email and text messages all provide information, sometimes information people don’t even know is there. An investigator might even be able to have the carrier provide information on web habits when the owner is using the carrier’s data network to web surf.

3. Digital Cameras: The newer the camera, the more data it may provide the forensic investigator. A few years ago a camera might provide a time and date stamp. Today it may provide that plus geo-location data, social media information, and any information in the memory card. While not as information rich as a smart phone, many digital cameras provide a wealth of information through photos and sharing data.

4. OnStar and similar services: Car support services like gather data about the automobile and its passengers, though passenger data is limited to what they say through the system and any fiddling with controls like the radio or A/C. Today that information is includes communications with OnStar representatives, location data, approximate speed, and how you use the features in the car. In the OnStar style services may provide other data for the forensic investigator.

5. Search Queries: It is no secret that search engines use the information they learn about us to target advertising. Less known, but no less true, is that even when search data has been ‘anonymized’ to hide who it came from, it is possible to track back to a person using their search data. Forensic investigators can use the searches coming from a single person to identify that person, even if the data is supposed to be anonymous.

6. Hidden Files: Hidden files like print spool files can provide a lot of information. Files can be viewed on a computer without being on the computer hard drive. A web page or a document on a thumb drive may be viewed without leaving any evidence on the computer. But if the document is printed the print spool document will be on the hard drive. Swap files – information saved to the hard drive when RAM is needed – contain information that resided in RAM, but may never have existed on the hard drive. Some applications create their own version of swap files as part of their memory management.

Forensics has changed much over the centuries. Computer forensics has seen as much change in a few decades. Of the six unexpected places for an investigator to find clues listed above, three were either negligible or nonexistent ten years ago. As technology advances, the field will continue to change and grow, and forensic investigators will continue to change and grow with it.

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Day to day tasks might include questioning suspects, studying demographic data, behavior, and creating criminal profiles.  Criminologists are required to maintain extensive records and write reports of their findings, as well as making presentations to law enforcement agencies and their peers.  Shift and overtime work is frequently required, but as you gain experience, positions may open to you at consulting firms, or with governments and universities.  According to the , the field is expected to grow faster than average between now and the end of the decade, and people with advanced degrees can be expected to be offered the best opportunities.

Is criminology the right field for you?  

Criminology is a fast-paced, exciting, and demanding field, and people who are attracted to it are generally interested in bettering society, but are stimulated by the atmosphere and climate that the position brings, and the type of energy it requires.  If you have passion for the description, this might be the right field for you; there are many different aspects of positions in criminology that might further fuel your interests:  technology, foreign cultures and languages, performing in depth analyses, science, extensive research, and community outreach are all sub-fields of the career path that might excite you.

Within the career field, and the agencies that employ criminologists, there are a number of subsets of the position that require personnel with a variety of backgrounds, including statistics, graphic design, IT, accounting, investigators, sociologists, engineers, and linguists to mention a few.  A degree in criminology is a primary requirement for entering the field, and advanced degrees are helpful. In a program designed to help you advance in this career field, you will study a core group of subjects, like criminal psychology, sociology, math, science, communications, statistics; physical, life sciences, and geography are also helpful, depending on what aspect of the field you are going to pursue.

Advanced degrees add specializations to your core learning, and may amplify on the subset field you have selected for your career in criminology.  What courses you choose will be dictated by your chosen subset, but may include more advanced studies, specifically in some of the areas mentioned previously.

Master’s and Doctoral programs will provide you with the opportunity to conduct specific research in your area, and often include practical working internships with agencies that have relationships with your school.  A thesis and final exam, written or oral, will cap off your graduate studies in criminology, and amplify the knowledge gained in your undergraduate program.

Joint degrees, like Masters in Criminology combined with Masters in Public Administration prepare you for field management positions for state and local governments.  A career in criminology can be a non-stop roller coaster ride of excitement and hard work, while all the time knowing you are helping the community you live in.

On November 30, 2001, as he was leaving the Renton Truck factory where he worked, he was arrested for the murders of four women whose cases were linked to him through DNA sampling. As part of a plea bargain, wherein he agreed to disclose the whereabouts of still missing women, he was spared the death penalty and received a sentence of life imprisonment without parole.

Ridgway was born in Salt Lake City, to Mary Rita Steinman and Thomas Newton Ridgway. He had two brothers and was raised in the McMicken Heights neighborhood of Sea Tech, Washington.

His homelife was somewhat troubled, as he witnessed more than one fight between his parents. As a boy, he had the habit of wetting the bed, and his mother was always the one to discover this. She would immediately bathe him and then humiliate him in front of the family, which had a deep impact on the young Gary Ridgway. From a young age he had conflicting feelings of sexual attraction and anger towards her, which will define him later as the Green River Killer.

As a young child, he was tested with the IQ of 82, signifying low intelligence (criminal investigators often point out that murderers are not always criminal masterminds), and had trouble in school, having to repeat a single year twice in order to pass. While in high school, he joined the navy and was sent to Vietnam, serving onboard a supply ship.

His friends and family described him as friendly but strange. His first two marriages resulted in divorce because of infidelities by both partners. Both wives claimed that he had placed them in chokeholds. In 1975, his second wife gave birth to his son, Matthew.

Throughout the 80s and 90s, he is believed to have killed 71 victims, according to hi testimony, some as young as 12 years. The victims are believed to be either prostitutes or runaways, picked up along Pacific Highway South. Most of the bodies were dumped in wooden areas around the Green River (Washington). The bodies were often left in clusters, sometimes posed, usually nude. He sometimes would return to have sexual intercourse with them (necrophilia). Because of the advanced decomposition, four bodies are still unidentified. Ridgway would sometimes contaminate the scene with gum, cigarettes and written material belonging to others, and he even transported some victims’ remains across state line to Oregon to confuse the police.

In the early 1980s, the King County Sheriff’s Office formed the Green River Task Force to investigate the murders. The most important crime scene investigators amongst them were Robert Keppel and Dave Reichert, who periodically interviewed incarcerated serial killer Ted Bundy. The interviews were of little help in solving the case.

Gary Ridgway was first arrested in 1982 on charges related to prostitution but became a suspect in 1983. In 1984 he passed the polygraph test which seems to indicate some form of sociopathy. It wasn’t until 2001 that DNA linked semen collected by forensics from the victims to saliva collected by the police from Ridgway. Some other victims were added to the list after investigators found microscopic spray paint spheres on the victims, being a specific brand used in the factory at Kenworth during the specific time frame.

In 2003 the now imprisoned Green River Killer made a plea bargain so he would not be executed and led the crime scene investigators to 42 victims and confessed for another 29. He confessed to more confirmed murders than any other American serial killer. On December 18 he was sentenced to 48 life sentences with no possibility of parole and another 480 years for tampering with evidence (10 for each victim).

Here is what crime scene investigators tell about the crime:

Mark Twitchell registered as a woman on an online dating service so he can lure his victim to the garage of a rented house. CSI agents agree that this is a very common ruse used by criminals to lure unsuspecting victims into their traps.

The crime scene investigators found a gruesome scene when entering that house. When he arrived, John Altinger was hit on the head with a blunt object (a metal pipe), stabbed to death and then his body was dismembered using a hunting knife. The murderer then tried to burn the victim, but, unable to do that, he dumped him into the city sewer.

Crime scene investigators found a thirty page long text on Mark’s computer which depicted the details of the murder. The text was written in first person and began with “This is the story about my turning into a serial killer”.
The chief criminal investigator, detective Bill Clark, is convinced that the amateur filmmaker is a very dangerous killer:

“In my opinion, we are talking about a psychotic killer that we managed the get off the streets of Edmonton. In my and my colleagues’ belief there is no doubt – if he wouldn’t have been caught, he would have killed again”.

With a few days prior to this murder, Mark Twitchell lured another man into the same trap, but that one managed to get away.

During the trial, Mark Twitchell claimed that it was all a joke and the victim became furious about it and attacked him. He claims that stabbing his victim in the heart was, in fact, self defense. Forensic science as well as forensic psychology were important in the jury’s decision, who did not believe this theory and sentenced him to life in prison.

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Gary Ridgway – Green River Killer

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