Grammy-winning singer Chris Brown is under investigation for an alleged assault in a West Hollywood parking lot, the Los Angeles County Sheriff’s Department said early Monday.

Deputies responding to a report of six men fighting Sunday night found the scene clear but were told by witnesses there had been a brief fight over a parking space, according to The Associated Press.

“The altercation allegedly led to Chris Brown punching the victim,” the department said in a statement.

TMZ.com, which first reported the fight outside the Westlake Recording Studio, said it also involved Frank Ocean, one of the top nominees at the Grammy Awards next month. No arrests were made.

Ocean later tweeted he “got jumped by [Brown] and a couple guys” and suffered a finger cut.

It wasn’t Brown’s first problem in the run-up to the Grammys. His attack on singer Rihanna on the eve of the 2009 awards event overshadowed the show. Last June, he was injured in a brawl with members of hip-hop star Drake’s entourage at a New York nightclub.