The Associated Press
OMAHA, Neb. (AP) - A University of Nebraska at Omaha study contends that using DNA sweeps, like the one used by the Omaha Police Department in a serial rape case, is not an effective way to solve crimes.
The report shows that only one in 18 known sweeps in the nation has identified the person responsible for the crime.
Criminal justice professor Sam Walker wrote in the report released Wednesday that testing large groups of potential suspects is “extremely unproductive.
“There’s just a tendency for the police to think that this is some kind of magic tool,” Walker said. “It sort of encourages sloppy and lazy police work. And it consistently fails to produce important results.”
The report, by the Police Professionalism Initiative at UNO examined 18 murder and rape investigations in which police collected DNA on a mass scale. The one case that was solved by a DNA sweep involved a comatose woman who was impregnated in a Massachusetts nursing home, Walker wrote.
In that case, police were able to narrow the test to the 25 workers who would have had access to the woman, Walker wrote.
Four cases, including Omaha’s, have not been solved.
The report says the remaining 13 were solved through a tip, a witness account or some other traditional route.
Walker also wrote in the report that often, such sweeps can cause more legal problems than they can help cases.
The investigation in Omaha has drawn ire from state Sen. Ernie Chambers and the Omaha chapter of the NAACP.
The DNA samples were collected as part of an investigation into at least four unsolved rapes of 17- to 21-year-old black females in Omaha that police believe were committed by the same person in the last two years.
Police Chief Thomas Warren held a news conference in late June defending the DNA samples, saying it was not a random search.
Based on descriptions given by four victims and other evidence police said they believed the suspect is a 23- to 40-year-old black man, about 5-foot-3 to 5-foot-9, between 175 and 250 pounds, who may have worked for the Omaha Public Power District.
After obtaining a court order for the names of 84 black men who worked or had once worked at the power district, police whittled the names down to 32 based on their investigation. Warren has said four people voluntarily submitted to DNA testing and nine people were not asked for DNA samples based on their physical characteristics.
“It is the opinion of this department that DNA technology is an effective investigative tool,” Warren said in a statement. “It will provide evidence that will implicate the individual responsible for these crimes or eliminate individuals as possible suspects. It is a legal and efficient investigative tactic.”
Walker’s report also mentions the Kearney Police Department’s collection of DNA from 75 men in a 2002 serial rape investigation. Walker noted in the report that the Kearney case was eventually solved through a tip.
But Kearney investigators said they couldn’t have eliminated suspects as quickly without DNA.
“I understand that police are under tremendous pressure to catch someone in these cases,” Walker said. “But we can’t let that kind of pressure lead to tactics that are both ineffective and probably illegal.”