Police unions fight against policies requiring officers to provide samples of their DNA.

When police in southern Louisiana were investigating the deaths of eight women in 2009, the sophistication of the crimes set off rumors that the serial killer was a police officer - speculation that became so pervasive that officials ordered DNA testing of law enforcement personnel to rule it out.

All local officers agreed to the testing and were eliminated as suspects, but the killer remains at large, said Jefferson Davis Parish Sheriff Ricky Edwards.
Having officers' DNA samples on file is important for saving time in investigations and fending off doubt about evidence at trials because it allows authorities to identify unknown genetic material found at crime scenes, Edwards and other police and crime lab officials say.
Police in other parts of the country, however, are not as willing to hand over their DNA. Rank-and-file police from Connecticut to Chicago to Los Angeles have opposed what some experts say is a slowly emerging trend in the U.S. to collect officers' DNA.
Experts say policies requiring police officers' to give samples of their DNA have been slower to catch on in the U.S. because police unions have more power here.

Lisa Hurst, a senior consultant with the lobbying firm of Gordon Thomas Honeywell, said that as DNA technology advances, it's more important that officers' DNA is on file to eliminate unknown samples found at crime scenes.
"Today's tests pick up a high amount of samples," said Hurst, whose firm lobbies for the DNA industry and advises governments on DNA legislation. "They need to make sure that this unknown (DNA) profile isn't from a detective or patrol guy who accidentally sneezed while walking through the room."
It's especially important, she said, for eliminating reasonable doubt at criminal trials.
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