Zombie CSU (16 page)

“An interesting point is whether or not zombies perspire,” says Leadbetter. “It they do, then it would be quite feasible that they would be able to leave fingerprints. Should it be that they do not perspire, then they would always be capable of leaving fingerprints in soft substrates such as chocolate, excrement, blood or toothpaste for example provided that the fingerprint detail did not break down before they joined the zomboid world. It would be interesting to note here, that due to the awkwardly articulated gait of the average zombie, the quality of fingerprint deposited by them would doubtless be subject to smudging and excessive distortion.”

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DNA Testing

There are two primary kinds of forensic DNA testing: RFLP and PCR. RFLP (restriction fragment length polymorphism), is the more accurate of the two and is often called “DNA fingerprinting” or “profiling” and this involves the examination of sequences of base pairs in a section of a DNA strand. Since each DNA strand is unique, the identifiers in two samples will either match up (indicating they came from the same source) or they won’t, hence the reference to “fingerprinting,” which also matches specific patterns believed to be unique in each person. Though this is a very accurate test, RFLP has a downside in that it requires a fair amount of collected sample cells, such as large spatters of blood or several strands of hair. These samples also have to be fresh, undamaged, and only recently dead. The other downside to RFLP testing is the time involved: which is anywhere from two weeks to three months.

The PCR (polymerase chain reaction) test is less accurate, but police can get an answer in as little as a few days; this DNA does not have to be recently collected or fresh.

Expert Witness

“DNA testing has done a lot of good for the legal system,” says Georgia Stanley, a DNA testing technician for an independent New Jersey testing firm. “Not only is it contributing to the arrest of more criminals—and with a higher degree of certainty that they
are
the actual perpetrator; it is also helping to free persons wrongly convicted of crimes. Naturally courts would prefer the RFLP results because of their much higher degree of mathematical accuracy, but on the level of police work the less accurate but much faster PCR is very often used. The advantage there is that police can often identify a lead suspect and focus their investigation. Later, more elaborate testing may be ordered by either prosecution or defense.”

Donna Sims, another technician at the same firm, explains the range of DNA testing. “We get all kinds of test requests, not just crime. Over the last eight years that I’ve been here I’ve done testing to identify suspects based on DNA found at a crime scene; to identify plane crash victims; to identify animals on the endangered lists in the Jersey Pine Barrens; to exonerate people wrongly jailed for crimes they didn’t commit; to verify blood relations as part of an estate settlement; and to match organ donors and recipients.”

The Zombie Factor

The zombies in a more advanced state of decomposition would be less likely to leave behind identifiable prints, but DNA touch evidence would still be useful. Examining its DNA through computer sequencing can identify any type of organism. Identifying unique individuals within each species is a bit less precise, but nowadays human DNA samples can be matched to the level of mathematical certainty. DNA testing may not be much help in the first hours of a manhunt, but once the zombie has been captured or killed, its DNA can provide information to investigators that will help them identify the person the zombie formerly was and then backtrack his movements, hopefully to the source of the contamination.

In the longer run, scientists and doctors will examine the zombie DNA in order to understand the nature of the disease and/or mutation that created this flesh-hungry monster.

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Bloodstain Pattern Analysis

Violence happens, blood spills. Bloodstain pattern analysis (BPA) is a hot topic in forensic science. Blood spatter
¹⁰
is crucial evidence in many cases in that it can often help police positively ID victims and assailants. Advancements in DNA analysis have given this aspect of forensics a major boost, and along with blood typing and other tests, it provides law enforcement and the courts with potent weapons for apprehension and conviction.

BPA is the science of examining the distribution, locations, and shapes of bloodstains at a crime scene. Properly done it allows the expert to accurately determine the sequence of events during the commission of a violent crime.

This field encompasses many other areas of science and medicine, including biology, chemistry, math, physics, anatomy, and others.

The blood spatter expert has a complicated job and will attempt to:

 


Locate all individual stains and patterns.


 


 


Calculate the angle of impact for each stain in order to determine the direction from which the blood was traveling. (Remember, a bloodstain may be present when the victim and/or assailant is not.)


 


 


Describe each through notes, photos, and other recording methods.


 


 


Determine the approximate number of blows.


 


 


Determine the likely sequence of events.


 


 


Determine the mechanism that created each stain. Blood from a torn artery will be different from blood spray from a baseball bat to the head.


 


 


Determine the number of people present at the scene during the attack.


 


 


Determine the position of the victim and/or assailants during the attack. This takes into account any objects on the scene that a person may have encountered, touched, collided with, etc.; and objects that might have altered or interfered with the trajectory of blood.


 


 


Determine the probable weapon used in the attack (knife, gun, teeth…)


 


 


Determine the source of each bloodstain.


 


 


Locate wounds on the victim and/or assailant that correspond with spatters.