The 27-year-old former child star first alleged during her arraignment on Friday that police illegally entered her apartment after being called to her midtown building. But in a Twitter message believed to be from the troubled actress posted Saturday, Bynes alleged that her arresting officer also sexually assaulted her.
"As it would with any such allegation, regardless of its credibility, IAB is investigating it," said the NYPD's chief spokesman, Paul Browne, referring to the internal affairs bureau.
The Twitter handle used to make the sexual assault allegations Saturday does not appear to be verified by the social network but Bynes' friend, former Hollywood publicist Jonathan Jaxson, said Saturday the tweet was made from Bynes' account. Twitter did not immediately return a request for comment.
In court on Friday, the former "Hairspray" star made no mention of the sexual assault allegations, though she did complain of illegal entry to her apartment. She's been charged with reckless endangerment, attempted tampering with evidence and unlawful possession of marijuana.
A law enforcement official who spoke to the Associated Press on the condition of anonymity because of an ongoing investigation said the building manager was with officers at Bynes' apartment when they arrived Thursday night. The official said officers were kept waiting approximately five minutes before she opened the door to them. The same official said the building manager told internal affair investigators nothing untoward happened.
Bynes was released by Chief New York County Judge Neil Ross on her own recognizance because, Ross said, he did not believe her to be a flight risk. But in releasing her, Ross also issued a stern warning to Bynes, telling her not to get rearrested or miss any court dates. She's due back in court on July 9.
Attempts to reach Bynes' arraignment lawyer were unsuccessful Saturday evening.
Bynes rose to fame starring in Nickelodeon's "All That" and has also starred in several films, including 2010's "Easy A." But she has been in the news more recently because of several scrapes with the law and bizarre public behavior.
Bynes was arrested Thursday night after building officials called police to complain she was rolling a joint and smoking pot in the lobby. The officers went to her apartment where they saw heavy smoke and a bong sitting on the kitchen counter. They said she tossed the bong out the window in front of them, prosecutors said Friday.