DURHAM - Sgt. Mark Gottlieb and Investigator Benjamin Himan, the Durham Police Department's principal investigators in the Duke lacrosse case, have both left the department in the past several weeks, Chief Jose L. Lopez said Tuesday.

Gottlieb, who joined the department in 1992, had contemplated leaving for a few months, Lopez said. "I did not ask him to leave," Lopez said. "I wasn't looking for his resignation."

Lopez said Himan, a Durham officer since 2002, resigned unexpectedly in mid-February for what Lopez termed personal reasons.

Gottlieb was transferred from investigations to uniformed patrol in November. Police said the change was part of normal department restructuring.

Gottlieb and Himan were criticized for failing to question discrepancies in the story of Crystal Gail Mangum, who accused the lacrosse players of gang-raping her at a team party in March 2006. The players were cleared of all charges and declared innocent by North Carolina's attorney general last year.

Defense lawyers have alleged that Gottlieb fabricated evidence to bolster Mangum's identification of the three charged players. When Gottlieb and Himan first interviewed Mangum in March 2006, she gave vague descriptions of the three men who allegedly assaulted her, as recorded in Himan's notes: "white male, short, red cheeks fluffy hair chubby face, brn"; "Heavy set short haircut 260-270 [pounds]," and "Chubby."

None of Himan's notes came close to matching Collin Finnerty, who is tall, baby-faced and lanky.

Four months later, Gottlieb typed up his account of the interview, giving spot-on descriptions of the three indicted players, including this description of Finnerty: "W/M, young, blonde hair, baby faced, tall and lean."

Gottlieb also came under fire for focusing on Duke students when he was patrol supervisor in a district that included Duke University.

The lacrosse case fell apart amid allegations by defense lawyers that Gottlieb, Himan, former District Attorney Mike Nifong and others engaged in misconduct, used improper procedure in a photo lineup and fabricated evidence. They are among the key points of vulnerability for the city of Durham in its defense of a federal civil rights lawsuit brought by the exonerated defendants against the city, Nifong, Gottlieb, Himan and other officials. Gottlieb and Himan will still be defended by the city in the suit.

Both former officers have filed separate motions to be dismissed from the suit. Gottlieb's motion, like the city's, argues that Nifong, now disbarred for his misconduct in the lacrosse case, ran the investigation. Gottlieb's motion also stated that he should have immunity from civil liability, even if he "engaged in conduct that somehow violated plaintiffs' constitutional rights."

(Staff writer Joseph Neff contributed to this report.)