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.
"From a civil liberties standpoint, there are a lot of red flags," said Connecticut Trooper Steven Rief, former president of the state police union.
"It's not that the law enforcement officers are opposed to giving up their DNA," he said. "You need to have safeguards in place. Something that can tell you ... something intimate about someone needs to be treated with the utmost care."
Rief and officers in other states say their concerns include management using the DNA information to see if employees are predisposed to diseases and to predict workers' future health problems. The rank-and-file also don't want their DNA placed onto a national database that holds criminals' genetic data.
Connecticut state police officials tried to get the legislature to approve a law requiring officers to provide DNA samples in 2009, but the bill died during the session after Rief and others spoke out against it at a public hearing at the Capitol.
In Chicago, police officers rebelled with a work slowdown in 2008 because of resentment toward their new chief over several issues, including a new policy to collect DNA from officers working at crime scenes.
In a still-unresolved dispute in Los Angeles, the police union and top brass have traded salvos over a requirement that officers give DNA samples in shootings involving police and other use-of-force incidents. Union leaders say management won't restrict how the DNA information is used and stored, and the union cautioned officers in 2009 about potential privacy and misuse problems.
The union, the Los Angeles Police Protective League, has been waiting for the department to force an officer to provide his or her DNA, which it hasn't done yet, so it can challenge the policy in court, a union spokesman said.
A small number of police departments across the country have limited policies on collecting officers' DNA. New York and Las Vegas, for example, require samples from crime scene investigators.
Louisiana appears to be the only state with a law requiring officers to provide genetic samples. The law was enacted in 2003 and applies only to officers hired on or after Aug. 15 of that year.
During the investigation of the serial killings in Jefferson Davis Parish, about 70 miles east of the Texas line, Edwards said officers in his agency and the Jennings Police Department who were hired before the DNA law took effect voluntarily gave samples of their DNA.
"I think it's a good tool that we're utilizing," Edwards said. "I see it as potentially going all the way across the country.
"I realize that there may be some privacy concerns," he said. "We should be leaders in saying we don't have a problem doing it."
Police in other parts of the world, including the United Kingdom and Australia, have been keeping officers' DNA on file for several years. The U.K. is also known for starting the world's first government DNA database of criminal suspects in 1995. The U.S. followed suit and now has the world's largest DNA database of criminals with 10 million profiles.
Some 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.
"If there's one unknown sample at the scene, the jury may give the defendant the benefit of the doubt," Hurst said.
Unknown DNA samples have caused problems in some criminal investigations, especially in the case of the so-called "phantom killer" in Europe. DNA from that woman was found at the scenes of about 40 crimes in Germany, Austria and France in recent years, ranging from burglaries to the shooting of a policewoman.
But the search for the woman ended with an embarrassing discovery in 2009: the DNA came from an innocent worker at a company that made the cotton swabs used to collect evidence.
Rief, the Connecticut trooper, said that while collecting DNA can be a good thing for criminal investigations, it also presents a host of problems.
"If we're just having a philosophical discussion about solving crimes and collecting DNA, why not collect DNA from everybody when they're born?" he said. "But I don't think we're ready to have that discussion as a society."
