a study in crime

Update on "Wilbur"; top left was taken on September 16th (seven days after leaving the pig out), top right on September 17th and the bottom on September 19th.

Decomposition happened quite fast because this was a small body, and it had been quite warm during the first few weeks of September. This would be considered the "dry" or skeletonization stage of decomposition...which is pretty self-explanatory.

Only the skin on the skull and some of the hooves were left, as it doesn't provide much for feeding larvae. Also, there hadn't been much rain during this time, so the conditions had been warm and dry. In a less exposed area (i.e. with little to no insect activity), the cadaver would have likely become mummified.

If you look at the head, you'll see that the eye hole in the skin doesn't match up with the eye socket in the skull. Keep in mind that there's no longer anything anchoring skin to...well, anything. So slipping does happen.

Passive: as the name suggests, these patterns have not had an external force. Examples include drips that result from gravity alone, transfer/contact, and pooling.

Altered: the stains have undergone some form of physical or chemical/physiological alteration. Some examples include clotting, insect interference, and dilutions.

Blood flow is a function of blood pressure (and other factors). A vessel that has been completely cut will have less pressure than one that has only been partially cut. 

In many cases, the entry hole of a bullet (from a handgun, specifically) appears much neater than the exit hole. Entry holes or wounds tend to be round, and if the trajectory was not straight-on, then there may be an abraded side indicating direction of travel. The exit hole would appear torn, with jagged edges; this is mostly due to the loss of kinetic energy after the bullet has passed through something else (for example, the entry side of an object, the muscles and organs of a person).

A bullet that has passed through another object between entering a body will be destabilized by that object. Rifling on pistols give the bullet a spin, thus stabilizing the bullet and keeping it from tumbling in the air. If the bullet has passed through another object (or objects) before hitting a body, the behaviour of the bullet would have changed:

Since the bullet is no longer stabilized, the aim would be off. A bullet only travels in a perfectly straight line if unimpeded; now that it is destabilized and tumbling, its path is more random. Depending on the impeding effects of the obstructing object(s), the bullet may stray a little or quite a bit from its original path

The bullet might hit the body when it is not perfectly horizontal (again, due to tumbling). As such, the entry wound would appear more ragged, and at first glance, may look like an exit wound. It should be noted that skin or clothing around the entry would may be “pushed” slightly inward, as characteristic of an entry wound; conversely, the edges of skin or clothing around the exit wound, if there is one, may appear “pushed” outward, following the path of the bullet

Changed the theme of this blog. Following will be changes to the format of the content, as well as the tag page and the addition of resource pages.

This blog hasn't been update for some time, due to my workload.

I'm just letting you know that I will be taking the time after all of my exams have been done to revamp this blog. I'm just not as happy with the content and the layout.

And also, after finishing an intense semester of criminalistics, I have a lot more information to share.

This is regarding long-buried bodies that have had enough time to be fully decomposed. Unless the environmental conditions are cool and dry/arid, the body will begin to lose its biomass as detrivores consume the cadaver. Over time, this may result in a slight depression in the ground.

The Luminol of BlueStar (TM) products used for training will degrade DNA, as they are much cruder reagents. The products actually used in crime scenes will not degrade the DNA. It may dilute the blood evidence--but keep in mind that PCR is used during DNA extraction to "amplify" the amount of DNA present so that even a very small amount of DNA can be tested.

Furthermore, the use of Luminol or BlueStar, like all other evidence and procedures regarding a crime scene, must be documented via photography (as well as crime scene notes); one person must set the camera to accommodate low-lighting (longer exposure/shutter speed, larger aperture) and take the photo just as the other person sprays the reagent onto the surface.

Luminol and BlueStar must be prepared at the crime scene, just prior to use.There are various forms; some may be powder tablets that are dissolved in a spray bottle of sterilized/distilled water, and some may be two liquid parts that are to be mixed together.