While officials won't reveal the identity of the woman who they say called 911 early Sunday morning and identified Brown as her attacker, eyewitnesses saw a badly bruised Rihanna check into L.A.'s Cedars-Sinai Hospital Sunday. She and Brown were supposed to appear and perform at the Grammy Awards that night.
According to E! News, Rihanna, 20, checked out of the hospital Monday night and postponed a concert scheduled for Friday in Malaysia. She also canceled a Thursday concent in Indonesia. The L.A. Times reports she's cooperating with investigators to build a domestic violence case against Brown. Meanwhile, according to the National Basketball Association, Brown has pulled out of scheduled appearances at this weekend's NBA All-Star game.
Neither Brown nor Rihanna's representatives responded to ABCNews.com's requests for comment.
Brown's alleged violent behavior may be rooted in his past. In 2007, he told Giant magazine about how he grew up terrified, watching his stepfather abuse his mother.
"He used to hit my mom," Brown told the magazine. "He made me terrified all the time, terrified like I had to pee on myself. I remember one night he made her nose bleed. I was crying and thinking, 'I'm just gonna go crazy on him one day.' ... I hate him to this day."
Brown also told Giant he studied martial arts to defend himself. After a fight with classmates in which he broke out his moves, he begged his own mother not to go to the police.
"Don't go to no cops pressing no charges," he told her, according to Giant. "Like, we don't do that in the 'hood."
"Chris Brown is like the all-American guy," Giant editor in chief Emil Wilbekin told ABCNews.com. "He's hardworking and a great talent. He may just be reacting based on what he knows, but it's scary and surprising."
For Brown, fallout's come fast. Marvet Britto, founder of brand management firm The Britto Agency, speculated that the case against the R&B singer will doom potential product endorsements and spokesperson gigs.
"Chris Brown's pedigree is not a pedigree that is indicative of bad behavior," she said. "You wouldn't expect him to have bad behavior. His career is not built on transgressions the way someone like Lil Wayne's is. Lil Wayne has built a career on smoking weed and doing drugs; that's also the pedigree of most rap stars. Chris Brown is a teenage pop star, and with that comes a more wholesome persona. And also a larger responsibility because he's targeting and speaking to a younger audience, versus a Lil Wayne whose audience is more mature and able to differentiate fact from fiction.
"His foolish acts will greatly hamper his ability to continue to see lucrative endorsement deals and corporate sponsorships," Britto said. "This will damage him."
But, perhaps, not beyond repair. America loves a comeback. If Brown apologizes for his actions, seeks help and perhaps even uses this episode for inspiration, he could set his career back on track.
"He should be given an opportunity to redeem himself," Britto said. "He should be given the opportunity to show remorse and sincerity. And now, if indeed Rihanna is the victim, domestic abuse may have two of the biggest advocates anyone could dream to have. Maybe he needs help. Maybe this will inspire his lyrics. Maybe this will end up being a blessing."