Sources close to the investigation say the couple, who appeared lovey-dovey at a pre-Grammy party only hours before, began arguing over a text message Brown received from another woman.
Some publications are reporting this other woman is no other than Paris Hilton.
The argument escalated when Rihanna grabbed the keys to Brown's rented Lamborghini and tossed them out the window. Brown tried to find them, and when he couldn't, he became shockingly violent.
Police sources say Brown punched Rihanna so hard that her eyes were nearly swollen shut. She also said he choked her until she lost consciousness while telling her he was going to kill her. By the time she awoke, he had fled the scene.
A witness to the horrific event called police. To all the Chris Brown fans who are saying he could not have possibly done this because you think he's cute and you like his music, police have a witness who saw Brown do it.
(Of course, all are innocent until proven guilty in a court of law.)
Police say Rihanna was so badly injured that the immediately drove her to a local hospital in their squad car, rather than wait for an ambulance to arrive.
Photos circulated around the internet today purporting to show Rihanna's injuries, but have since been debunked as a cruel Photoshop effort.
Meantime, Brown's career is already flushed down the drain. Radio stations quickly pulled Brown's songs from their playlists, and companies with whom Brown enjoyed sponsorships are dropping his contracts, including Wrigley's gum and the Got Milk campaign.
"The Milk Mustache campaign is taking the allegations against Chris Brown very seriously," says the group 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. Mr. Brown's ad was launched last fall and is scheduled to end this week."
Kanye West spoke of his concern for friend Rihanna on Ryan Seacrest's radio show.
"I don't want to speak too much on it, but I was completely devastated by the concept of what I heard," he says. "Rihanna has the potential to be, you know, the greatest artist of all time and, in that sense, I feel like she is my baby sis. I would do any and everything to help her in any situation."
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