DURHAM - It was the possibility of DNA evidence that drove an investigation involving two former Durham police officers and a prostitute. But in the end, it was a lack of such evidence that led state prosecutors to decide not to file charges of sexual misconduct against the two men.

"The DNA tests did not support the position of the confidential informant, and that was a factor in the decision not to bring charges," Noelle Talley, a spokeswoman for the Attorney General's Office, said Wednesday.

Talley wouldn't say whom the DNA belonged to, citing a state law allowing DNA results to be part of a criminal investigative file, which is not public. She also declined to say whether prosecutors considered any other evidence in their decision.

Sgt. Keith Cheeks and Officer Demond Gooch were alleged to have had sexual relations while on duty, on separate occasions, with Diana McKinney Denby. Denby told police she had encounters with both men on Oct. 17 and Nov. 4 last year, and she gave investigators DNA evidence after both incidents.

Detectives attempted to corroborate Denby's claims through undercover means, but a chase and shooting incident on Nov. 6 blew the investigators' cover. Two days later, Chief Jose L. Lopez Sr. disclosed that an investigation of "possible sexual misconduct" was under way.

That inquiry began with five officers but quickly narrowed to Cheeks and Gooch. They were publicly associated with case in January when the department announced their resignations for unspecified misconduct. Police said their investigation did not substantiate Denby's claims.

DNA samples were collected from the two former officers in late November and from Denby in December.

To avoid any conflicts of interest, Durham District Attorney David Saacks forwarded a report on the case to state attorneys in May. Cheeks had testified in one of his cases years earlier.

Saacks said Wednesday that he initially thought there wasn't enough evidence to prosecute the former officers.

Denby, the accuser, will not face any criminal charges, Talley said.

Efforts to reach Cheeks, Gooch and Denby on Wednesday were unsuccessful.