Crime Library: Criminal Minds and Methods

The Murder of Daniel Williams

A New Lead

In 2003, the California Department of Justice gave local police departments a grant to reopen old cases in which DNA evidence had been found. The state had just completed a new database containing the DNA records of thousands of convicted felons. The Department of Justice wanted DNA samples from unsolved cases to run through its databank of known criminals.

Patch: California Department of Justice
Patch: California Department of Justice

Back in 1998, the LAPD Crime Lab had not found any sperm or semen in the condom recovered in the Daniel Williams investigation, but SID criminalists had found a tiny number of epithelial cells from both the inside and the outside of the condom. Epithelial cells are skin cells from the lining of mucus membranes such as those found inside the lips, the nose, the rectum, and the genitals.

Larry Blanton, SID Expert
Larry Blanton, SID Expert

No DNA profile had been extracted from the cells because there was nothing to compare it to. In 1998, DNA was new to the world of forensic technology and California did not have a DNA database. DNA matching could only be used if investigators developed a suspect from whom they obtained a DNA profile.

An additional problem in Daniel's case was that there was only enough DNA source material — the epithelial cells — for one try at a DNA extraction. A single test would consume the entire sample.

To even try to remove the DNA material from the sample risked destroying what little physical evidence they had.


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