Rihanna, Chris Brown

Prosecutors won't press charges based on the initial investigation of Chris Brown, but asked officers to gather more evidence as they decide whether to proceed against him.

The Los Angeles Police Department presented the case to the District Attorney's office Tuesday, but prosecutors felt a deeper investigation was warranted, The Associated Press reports. D.A. spokeswoman Jane Robison told TVGuide.com that police have 30 days to investigate after a person posts bail. Brown was released on $50,000 bail Sunday night.

Meanwhile, Brown's once clean-cut, nice-guy image continues to suffer. The 19-year-old, whose Wrigley Gum ads were suspended Monday, will no longer be involved with the Got Milk? milk campaign once his contract ends this week, and his songs are being dropped from radio playlists.

"The Milk Mustache campaign is taking the allegations against Chris Brown very seriously," the campaign said in a statement. "We are very proud and protective of the image of the Milk Mustache campaign and the responsible message it sends to teens."

Police have yet to release the identity of Brown's accuser, but various outlets have identified her as Rihanna, Brown's girlfriend of a year. She is cooperating with police, E! News reported. The 20-year-old has told police Brown choked her and threatened to kill her Sunday evening during an argument in Brown's car, a source close to the investigation told E!. Rihanna reportedly also lost consciousness.

Both stars have canceled a slate of appearances, starting with their scheduled performances at Sunday's Grammys. Brown pulled out of his NBA All-Star duties this weekend, while Rihanna canceled concerts in Kuala Lumpur and Jakarta scheduled for this week.

Brown has yet to publicly comment on the incident. His stepfather, Donnelle Hawkins, whom Brown has accused of abusing his mother, told Access Hollywood he "wouldn't be surprised" if Brown hurt Rihanna.

"[Chris] has to take responsibility for his own actions," said Hawkins, who denies abusing Brown's mother.