Updated

A New York City police officer has pleaded not guilty to charges he raped a woman while off duty.

Michael Pena is being held on $500,000 bail after his arrest last month. He entered the not guilty plea Wednesday to an indictment charging him with rape and sex assault.

Authorities allege that Pena was drunk when he approached the 25-year-old woman in upper Manhattan and asked her how to get to a subway stop. They say he grabbed her, ushered her several blocks to an apartment building backyard, and raped her.

The 27-year-old officer was arrested after the woman ran to officers and warned them he had a gun. Police say the officers didn't realize Pena was a colleague until they found his police ID.