SAN DIEGO -- A veteran sheriff's detective, accused of sexually assaulting a prostitute in Mission Valley while on duty last winter, pleaded not guilty Thursday to five felony charges, including sexual battery by restraint.

Thomas John Sadler, 47, faces about eight years in prison if convicted, said Deputy District Attorney Jeffrey Dort.

Sadler stood with his hands folded as his attorney, Michael Berg, successfully argued that bail be reduced from $250,000 to $100,000.

Sadler, a 23-year veteran of the Sheriff's Department, posted the higher amount following his July 31 arrest at his Santee home. He was hospitalized the next day after trying to commit suicide.

Berg said Sadler's brother had put up his home to help the defendant make bail, and the lower amount would allow his sibling to pull his house out of the bail agreement.

Judge David Szumowski ordered Sadler not to leave San Diego County without permission of the court.

Sadler -- who was assigned to the Lemon Grove substation -- is on administrative leave from the Sheriff's Department while his case is pending, Berg said. A readiness conference was set for Oct. 21 and a preliminary hearing for Dec. 9.

"We intend to aggressively defend him against all the charges," Berg said outside court. "He is absolutely convinced there's been no wrongdoing on his part whatsoever."

Berg said Sadler, whose wife accompanied him to the courthouse, will be looking for other employment to meet his expenses.

"Right now he's getting over the shock of actually being charged on this case," the attorney said.

Besides sexual battery, Sadler is charged with assault and battery by an officer and false imprisonment by violence, menace, fraud or deceit, along with two counts of accessing a computer to defraud.

According to a declaration filed in support of an arrest warrant, the prostitute, who is in her 20s, was sitting on a curb in the 3100 block of El Cajon Boulevard in the North Park area of San Diego when Sadler, driving his unmarked work vehicle, pulled up alongside her about 10:30 a.m. on Feb. 6.

Sadler allegedly identified himself as a "sheriff's officer," forced the woman into the Ford Taurus and drove her to the 2800 block of Camino del Rio South, where he pulled over on the edge of a restaurant parking lot and forcefully fondled her.

Three witnesses called 911 to report what they took to be a kidnapping in progress, but Sadler fled before police arrived, according to the court filing.

The alleged victim and two witnesses later identified Sadler from a photo lineup, police said.

Sadler was accused of similar behavior in 2002, according to a lawsuit filed in federal court.

A 34-year-old woman, Nicole Bowman, said Sadler stopped her in a parking lot after she had left a bar, then searched her, pulling up her bra and looking down her pants.

Bowman said she filed suit after getting nowhere with the Sheriff's Department. The county of San Diego settled the case with Bowman for $10,000 a year later, according to court documents.