Chris Brown  is currently being questioned for alleged assault  on a female. Ryan Seacrest  and Ken Baker just talked about it during the Grammy red carpet coverage and said the incident took place at about 12:30 am this morning after the Clive Davis Grammy party and it was allegedly an argument that got out of control in a limousine. No further details are out at the moment including who the female is. When asked about Rihanna 's involvement, her rep said,  "Rihanna is well. Thank you for concern and support." Also, no word at this point on whether he will be able to make the Grammys this evening where he is scheduled to be a performer.
Update: It was just announced that neither Chris Brown nor Rihanna will be at the Grammys tonight.