LA Forensics: The Signature Murders
What's in the Dust?
An electrostatic detection apparatus operates by using a high voltage charge on a lifting film that causes dust particles to stick to the film's underside. While mostly employed for flat surfaces, it can be used on fabric, newspaper, and even bodies. With this device, SID technicians could go through Luis Garcia's apartment in the hope of finding a usable shoe impression, left in the dust.
While footprints made with shoes are considered to be "class characteristic," meaning they can't be associated with a specific individual, if there's anything unique about the bottom of the soles, such as a nick, the shoe impression may then yield individualizing traits that can be matched to a suspect's shoe. If not, SID can at least get the size and shape of the shoe.
The SID team brought in this device and found several prints, although they would have to work to eliminate people who had been in the home who were not the intruder — including paramedics and crime scene personnel.
Since a shoeprint was not the best type of evidence, but only added something if they had a good collection of other evidence, it was important to collect evidence that could be tied to a suspect with such specificity that there would be no doubt. Thus, the blood evidence was their most important focus at this scene.