Law enforcement sources tell TMZ Chris Brown is being investigated by the LAPD in an alleged assault on a female.
According to police, Brown and a woman whom cops refuse to identify were arguing inside a vehicle around 12:30 this morning when suddenly things allegedly turned violent.
Cops say they received a 911 call, and when they arrived they noticed the woman had visible injuries. We're told she then identified Brown as her attacker. Cops say Brown had left the scene by the time police arrived.
One of the law enforcement people put it this way -- the contusions "look like an MMA fighter or something ... [It] looked like she was growing devil's horns."
We've also heard that Rihanna may have suffered bite wounds on one of her legs and arms, however, one source close to the situation tells us he doubts that is the case.
Chris Brown has been booked on a felony criminal threats charge. If the D.A. files the case, domestic violence charges could be added.