NEW YORK (CBSNewYork/AP) — The Manhattan District Attorney’s Office is investigating rape allegations against the son of Police Commissioner Ray Kelly. A woman has filed a complaint accusing TV news anchor Greg Kelly of sexual assault.

LISTEN: 1010 WINS’ John Montone reports

Sources told CBS 2’s Pablo Guzman on Thrusday that a woman came to the 13th Precinct with her sister Tuesday night to file the complaint. According to reports, she said she met Kelly, co-host of “Good Day New York” on Fox 5 TV, near the South Street Seaport in October.

It is alleged that they had drinks, then went to her law office, where she claims she was sexually assaulted.

Police spokesman Paul Browne said the police commissioner was recently made aware of an accusation against his son by the boyfriend of a woman.

“Commissioner Kelly was approached by an unknown individual at a public event who told him that his son had ‘ruined my girlfriends life,'” Browne said in an e-mailed statement to CBS 2. “Commissioner Kelly asked him to explain and the man said he didn’t want to discuss it there, so the commissioner told him to put it in writing and send it to him.”

LISTEN: WCBS 880’s Paul Murnane reports

The investigation was turned over to Manhattan District Attorney Cyrus Vance on Wednesday because of a potential conflict of interest — a decision Mayor Michael Bloomberg agreed with.

“In this case, I thought the Police Department did exactly what they should do. They right away turned over the investigation to the DA because you don’t want the appearance of a conflict of interest,” he said.

Vance and his team will be searching for witnesses an evidence to support the woman’s claims she was drunk.  They are already weeding through surveillance videos from a Seaport bar and her office.

For investigators, it may come down to this: was she so drunk, she was not capable of saying no? That would support a rape charge.

“These are the worst cases because the fact of the matter is that if he knowingly forced himself on somebody who is saying no even though she started down that road, it’s still rape,” said criminal lawyer Gerald Lefcourt.

To back a claim that she was quite drunk, Vance will have to get witnesses who saw them drinking near the Seaport. And investigators are already searching for videos of Kelly and the woman at or near a bar, walking to her office, inside her building, and especially what they were like when they left.

“In my opinion the prosecutors are looking for every single piece of evidence that corroborates her or corroborates him,” said Lefcourt.

1010 WINS’ Juliet Papa with Mayor Michael Bloomberg

The mayor said he and Kelly are approached often by the public and anybody with a complaint is asked to send it in. He insists all complaints are taken seriously.

WCBS 880’s Rich Lamb With Reaction From Mayor Bloomberg

In a statement, Greg Kelly’s lawyer, Andrew Lankler, said: “Greg Kelly is aware that the New York County District Attorney’s Office is conducting an investigation. Mr. Kelly strenuously denies any wrongdoing of any kind and is cooperating fully with district attorney’s investigation. We know that the district attorney’s investigation will prove Mr. Kelly’s innocence.”

Greg Kelly has not been charged and has stepped away from his duties at “Good Day New York” while the investigation continues.

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