HONOLULU -- Police arrested a cab driver on charges that he sexually assaulted a passenger.

The alleged incident happened on Sunday after sources said a 23-year-old woman decided to take a cab home instead of drive.

Adrian Cohen, 46, has nine prior convictions, including felony car theft and drugs charges. He also has misdemeanor convictions for prostitution, harassment and driving under the influence.

Now he is charged with first-degree sexual assault -- a crime police believe happened in his cab.

The president of The Cab company said that Cohen has been an independent contractor there for about a year. However, Howard Higa said he did not know about Cohen's criminal history.

"If Mr. Cohen did have priors, which we didn't know of, he certainly wouldn't be working for The Cab," Higa said.

On Sunday, a 23-year-old woman got into Cohen's cab in Waikiki and wanted to go to Pearl Harbor, according to court documents. On the way to her destination, she feel asleep.

The cab driver took the woman near the Sand Island Wastewater Treatment Center where she said she was sexually assaulted, according to a source familiar with the investigation.

Court documents said that the woman woke up with Cohen sexually assaulting her.

She was then driven to Pearl Harbor, where she alerted military police.

"I'm shocked that this thing would ever happen with our drivers. I've felt that over the years we've built a real professional team of drivers," Higa said.

The alleged sexual assault is the third incident to rock The Cab company recently. First one of its drivers, Manh Nguyen, was shot and killed along with two other people on Tantalus in early July. Then driver Yu Kyu Kim was shot near Pearlridge Shopping Center in an apparent robbery.

Higa said his company is reeling from the recent violence. He said that his drivers all have city-issued taxi licenses and believed the city background check would screen out dangerous felons.

"In our opinion, when a driver comes with his taxi certificate we felt it's not necessary to redo the background checks. We just assume that if the driver has the taxi certificate, he's passed all the requirements, especially the background check," Higa said.

The city department for licensing taxi drivers said they do run background checks on all applicants. Drivers need to be free of major convictions in the past two years. At the time of Cohen's application, the city said he qualified.