UPDATED 04/01/11 3:50 p.m.

CHICAGO (CBS) — Sources say the two Chicago police officers under investigation for claims of sexually assaulting a woman have faced similar accusations twice before.

But in the earlier two cases, the women decided not to follow through with charges, sources tell CBS 2.

The Town Hall District officers are under investigation for claims that they sexually assaulted a 22-year-old woman after offering a ride back to her Rogers Park neighborhood home.

Police are now examining whether there is any camera footage in the Chevrolet Tahoe squad car the officers were using at the time, sources say. The camera is activated when the police lights on top of the vehicle are turned on.

Sources also say police are examining GPS records. This was how they previously determined the officers stopped at a liquor store and other places on the way to the alleged victim’s residence, the sources said. The officers under investigation are both 38 years old and are veterans of the force.

Every time an officer enters a vehicle, he or she must sign into the computer and camera to start a shift. This is what enables GPS, the source said.

On Thursday, CBS 2’s Suzanne Le Mignot spoke with the neighbor of the alleged victim, who asked to conceal his identity.

“I heard knocking, then a yell for help,” he said.

The officers found the woman as she was leaving a male friend’s apartment, where there had been drinking and a quarrel.

Interim police Supt. Terry Hillard said Thursday that the officers found the young woman as they drove their marked Chevrolet Tahoe squad car near Sheffield Avenue and Addison Street, which is in the Town Hall District. Earlier reports had indicated that the chain of events had started at Broadway and Granville Avenue, which is two police districts away and had raised questions about what the officers were doing there.

But their alleged behavior is enough for Hillard to express outrage.

“I must express my extreme disappointment and outrage at such accusations against members of this department,” Hillard said at a news conference at Police Headquarters on Thursday. “Rest assured that these allegations, if proven true, these officers will fully be held accountable and punished. I will not tolerate this type of behavior. The Police Department will not tolerate this type of behavior.”

Mayor Richard M. Daley praised Hillard’s handling of the case on Friday. He said there should be nothing made of the fact the incident happened under Hillard’s watch, less than a month after previous Supt. Jody Weis stepped down. Weis was hired, in large part, to crack down on high-profile problems with police misconduct.

LISTEN: Newsradio 780 Political Editor Craig Dellimore reports

Daley said incidents like this one can happen at any time.

“There could be one next week or the following week. This, unfortunate, happens, misconduct and I think Supt. Hillard responded very strongly,” Daley said.

The mayor declined to comment on reports that the two officers had been accused of sexual assault before, saying only that the department will “thoroughly investigate it.”

The police report for the incident indicates there was a sexual encounter in the officer’s police SUV on the way to the woman’s apartment in the Rogers Park neighborhood, where the three played strip poker.

Then there was another encounter with one of the officers in the woman’s bed.

The woman says she was intimidated, afraid to say no to sex.

She also says she tried to get neighbors’ attention by hitting the wall, and later running out of her place for help.

The neighbor said the woman “did ask for someone to call police.”

Police sources say the officers left behind mock turtleneck collars with the letters CPD embroidered on them, a cell phone, and a police belt-keeper.

“I’m not going to divulge specifics about evidentiary items that may have been recovered,” Hillard said.

A source says a supervisor is also being questioned, since no supervisor checked on the officers for more than an hour while they were on the call.

“Thousands of officers work long and hard hours day after day, night after night, proud to be members of this profession and proud to serve the residents of the city of Chicago,” Hillard said. “Our officers are dedicated to strengthening the relationship with the public and will not stand for anyone eroding that trust that they work hard to establish.”

Officers working outside Wrigley Field for the Cubs’ opening day told CBS 2 off camera that the case gives the department a black eye.

It also has put some people on edge. Andrew Homerding says he would not trust police to take his girlfriend home.

“Absolutely not. It’s gross, it’s disgusting,” told CBS 2’s Kristyn Hartman.

But Nancy Soprich said all officers shouldn’t be branded alongside the accused cops.

“I think those are just two bad apples, and it’s in every profession,” she said.

Watch & Listen LIVE