Crime Library: Criminal Minds and Methods

LA Forensics: West Hollywood Hustle

Analysis of
the Butts

Cigarettes can be terrifically productive items of evidence, because the individual who smokes them places his or her mouth on the end that gets discarded, yielding samples of saliva, and is generally the only person to have come into contact with it, so the evidence is more or less free of contamination. The brand can also help to identify the smoker.

Cigarette butt evidence is examined.
Cigarette butt evidence is examined.

In 1986, there was no DNA testing in the U.S., and even by 1989, it was expensive, time-consuming, and not available to all jurisdictions. Even the courts were divided over its use and admissibility. Thus, the type of test most often used for identification of bodily fluids was the ABO blood typing test, which determined whether a person leaving blood behind had type A, B, A/B, or O. Protein marker analysis identifying the distinct protein composition further refined the identification process.

The butts from both crime scenes were collected for analysis, but it turned out that the saliva on the butts from the 1986 murder had dried too much for a blood type analysis. Nevertheless, items from the victim's stolen car had yielded fingerprints, which proved to be a match to a man named Sergio Rodriguez. Yet this was a common Hispanic name and they did not know where to find him.

For now, the best evidence was the cigarette butts from the Bayis scene. To the relief of the investigators, the killer proved to be a secretor.

Cigarette butt evidence is tested.
Cigarette butt evidence is tested.

"As we started testing the cigarette butts," said SID Supervising Criminalist Larry Blanton, "some of the results showed that the possible suspect was a Type A secretor. Now a secretor status means they secrete their blood type in their bodily fluids, such as their saliva. We also did additional testing, the DQ Alpha test, and determined that one particular type was showing up common to the crime scenes."

This type was found in only about 7% of the population. That did not help to identify a suspect, but it was better than having no blood type at all, or having one commonly shared by a large percentage of people. Whenever the police did identify a possible perpetrator, the blood type could either confirm him as a possibility or definitively eliminate him.

Then, before detectives had fully reconstructed the Bayis homicide, the killer appeared to have struck again, much more quickly this time. It was in another jurisdiction, but detectives on the Bayis case met with detectives from the Northeast Division Homicide to discuss the similarities and to launch a coordinated investigation.

Watch this story and many others from the case files of the LAPD's Scientific Investigation Division, which solves crimes using cutting edge forensics. Only on Court TV. Learn more.

 

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