Durham, N.C. — Several police officers implicated in a Durham Police Department investigation into sexual misconduct involving prostitutes have been cleared of any wrongdoing and are back on duty.

Police Chief Jose Lopez said Thursday that fewer than five officers remain under investigation. Initially, about 10 officers, ranging from rookies to veterans, were involved in the probe.

The officers were placed on paid administrative leave last month pending the outcome of the internal investigation, which began in September.

"We're continuing with the investigation, putting evidence out to the lab to be analyzed," Lopez said.

Part of the evidence was DNA samples collected from the officers.

"Some DNA evidence we're going to be looking at ... but it's not everything we have," he said.

Lopez has refused to name any of the officers involved, but he said Thursday that the allegations involve one victim.

"We're looking to see if there are any other victims who will come forward," he said.

The department is taking its time with the investigation to be as thorough and exact as possible, he said.

The Durham County District Attorney's Office and the FBI are being kept abreast of the investigation's findings, he said. The FBI has been consulted to determine if any civil rights violations occurred.