Ausborne Blog

I’ve always been interested in forensic science, and yesterday I came across this explanation of serology, its origin, and its history.  It starts with a multiple murder case in Germany in 1901 when scientists needed to figure out how to identify whether or not the stains on a suspect’s shirt were blood and, if so, whether or not the blood was human.

The local prosecutor then heard a farmer’s report that a man who looked like Tessnow was seen fleeing from his field, and he then found seven of his sheep slaughtered.  Their legs had been severed and tossed about the field.  Tessnow was brought in for a line-up and the farmer had no trouble picking him out as the man who had run from his field.

Still, the police needed better evidence to tie Tessnow to the murders.  Then they heard about a test recently developed by a biologist, Paul Uhlenhuth, that could distinguish blood from other substances, as well as mark the difference between human and animal blood.  Tessnow’s clothing was given to Uhlenhuth for thorough examination and his conclusions marked a turning point in the history of forensic science.  He found dye, but he also detected traces of both sheep and human blood.

The article then goes on to talk about what, exactly, serology is.  It discusses some of the basics of crime scene investigation, including the differences between presumptive and further tests.  Presumptive tests are the tests that are used to identify whether or not blood is present at the crime scene.  The further tests then determine whether or not the blood which has been found is human or animal.  It documents the history of this testing, and takes the reader through the ABO, blood type analysis, and DNA tests.

Despite how well the crime scene may get cleaned up, even the finest trace of blood can often be detected and further tested.  It is often the case that while the perpetrator may scrub down the obvious places, he can still miss between floorboards, under pipes, and inside drains.  Merely by pouring water on some tiles at a murder scene and pulling them up wherever the water flowed beneath them, one detective found the only existing trace of the crime–blood.  His discovery so surprised the killer, who felt certain he’d done a through job of cleaning up, that he instantly confessed.

Blood pattern analysis is then discussed at great length.  This is truly fascinating.

Blood pattern analysis plays an important role in the reconstruction of many crime scenes.  For example, when a prominent Cincinnati physician appeared to be the victim of an apparent suicide, the spatter pattern on his hand and on the couch on which he lay told a story of murder instead.  The various types of bloodstains indicate how the blood was projected from the body via several factors …

The shape of the blood drop itself, according to Kennedy, can reveal significant information.  “The proportions of the drops can reveal the energy needed to disburse it in those dimensions.  The shape of the stain can illustrate the direction in which it was traveling and angle at which it struck the surface.  Choosing several stains, and using basic trigonometric functions, enables us to do a three dimensional recreation of the area of origin from which a blood-letting event occurred.”

O.J. Simpson’s 1994 trial is even brought up.

Criminologist Dr. Henry Lee testified that there appeared to be something wrong with the way the blood was packaged, leading the defense to propose that the multiple samples had been switched. They also claimed that the blood had been severely degraded by being stored in a lab truck, but the prosecution’s DNA expert, Harlan Levy, said that the degradation would not have been sufficient to prevent accurate DNA analysis.  He also pointed out that control samples were used that would have shown any such contamination, but Scheck suggested that the control samples had been mishandled by the lab—all five of them—and the jury bought it.

This is a long, long read, but it’s really very fascinating.