post mortem interval

Forensic Science: what is it?

WATSON REALIZED SOMETHING IMPORTANT!! And by that she means she was hit with the sudden realization that both Sherls and Watson never covered what Forensic Science is. And given the massive influx of new followers (thank you everyone, you guys are amazing!) Watson thought she should define forensic science and cover the sub-disciplines in the field. Due to the interdisciplinary nature of forensics, Sherls and Watson have a pretty general science background, so don’t be afraid to ask us about anything. 

Forensic science, in the most broad definition, is the application of any science to the court of law (both criminal and civil). Essentially, it is using the scientific method to help with court trials. It’s important to keep the law part in mind, because everything we do in the field, scene processing, evidence collection, evidence analysis, all the tasks are done with a goal in mind: to preserve the integrity of evidence so that it is viable in court. Their third job is to search, find, and collect possible evidence in an efficient manner to ensure fragile evidence isn’t lost, but also in a careful way so that the evidence is preserved properly and not contaminated. With that said, we have a very general knowledge of law, and it mainly pertains to the Criminal Code of Canada, while @scriptlawyer​ is the better person to go to for detailed law knowledge. 

The most publicly know facet of forensic science is crime scene investigation. These are the people that come in a scene in full Protective Personal Equipment/PPEs (bunny suit, gloves, goggles, mask, boot covers, etc.). Their first job is to protect the scene, make sure nothing is tampered with. The second job is to record and document the scene in a thorough manner (photography, video tape, hand written notes), to ensure that the scene can be revisited later in the future. 

Below, in no particular order, are brief synopsis of forensics in a given sub-discipline: 

Pathology – they are the coroners and the medical examiners, performs autopsy and is responsible for determining manner of death, cause of death, and estimating Post Mortem Interval/time of death (PMI) 

Biology/DNA – looks at the biology of the scene, including DNA and any other bodily fluids (blood, semen, saliva, urine, etc), when looking at DNA, will be intimately familiar with a process called Polymerase Chain Reaction (PCR), will also look at hair and fibre samples, botanical material, and soil 

Toxicology – the chemistry side of the science, examines compositions of drugs, glass, paint, explosives, soil, determines presence/absence of drugs and poison, alcohol, uses lots of fun equipment, refer to @scriptchemist​ 

Firearms – looks at firearms (we are hoping that is obvious), discharged bullets, spent cartridge cases, shotgun shells, ammunition, gun shot residue (GSR), approximating how far from the target a weapon was fire 

Fingerprinting – studying minutiae of fingerprint, comparing prints left behind in a crime scene to prints from known origin, there’s actually not a lot of work being done on how accurate fingerprint is, and fingerprinting is under a lot of scrutiny right now for lack of organizational structure (some one should change that) 

Computer/Digital – one of the new emerging fields, basically finding, collection, preserving, and examining data from digital devices (computers, cell phones, etc.) Sherls and Watson do not have enough technological background so we will refer everyone to @scripthacker​ 

Anthropology – deals with skeletal remains, differentiating between human and animal remains, determining approximate gender, age, height, race, and any physical injuries or osteo-diseases 

Entomology – uses insect (mainly flies and necrophilious insects), flies life cycle, and the cycle of arthropod successions to determine long term PMI 

Psychology/Behavioural – this is a subfield of psychology/psychiatry. In criminal cases, work tasks might include determining if a person is fit to stand trial, evaluate for behavioural disorders, looking at behavioural patterns to set up a profile. In civil cases, they might determine if an individual is competent to decide when preparing a will, settling property, or refusing medical treatment. Both of us do not have much experience in this field, and would like to refer you to @scriptshrink 

Documents – document analysis studies handwriting, type-writing, type of paper and ink, tries to authenticate sources, basically anything to do with documents, neither Sherls or Watson has much experience with this 

Odontology – this field looks at dental evidence when the body is unrecognizable. Enamel in the teeth are hardy substances and can last for a long time, identification of the person can be made based of characteristics of the teeth, their alignment of the mouth, the great thing about living is the first world country is that almost every one has a dental record. Bite marks compared to dental cast has also been used as evidence in court (see Ted Bundy), but Sherls and Watson are both leery about this particular field, since there are not a lot of research proving that there is a scientific basis behind the field

Engineering – looks at failure analysis, accident reconstruction, and causes and origins of fires/explosions, mainly looks at the structure sides of things (is there an engineering scripty around? Because Watson would love to see one)

Others Watson found while researching: theres units for polygraph and voiceprint analysis too apparently. We do not know much about these two fields either.

*Phew* We know there is a lot of information on this post, we are planning to break down a few things we mentioned here and go into more detail in future posts. Send us asks if you lovelies have any questions.

Fly of the Dead (Cynomya mortuorum)

Some combination of watching too many crime shows, studying anthropology, and following a lot of ‘vulture culture’ blogs allowed me to immediately recognise this as a blow fly.

This species has been studied extensively in forensic entomology: because it lays eggs on carrion, its life cycle is predictive of the post-mortem interval of human cadavers.

I saw a maggot-eaten dead crow on my walk today: it’s very possible this little friend hatched on it not too long ago. It’s all part of that meaningless and grim cycle of life!

S/he seemed very happy to pose for the camera.