Miami officials said they are investigating R&B singer Chris Brown, who is currently on probation for assaulting ex-girlfriend Rihanna, following reports that he may have been involved in the theft of a mobile phone. Celebrity news website TMZ.com reported that a 24-year-old woman filed a police report in Miami Beach for “robbery by snatching” and that Brown was the culprit. The TMZ report said the woman tried to take pictures of the singer as he was leaving a nightclub and Brown took her iPhone and drove away. The police rubbished the claims, saying the witnesses and evidence were being reviewed, after which any action would be taken. They did not confirm Brown’s involvement in the incident. Brown, 22, who won a Grammy award earlier this month, is currently midway through a five-year probation after pleading guilty to criminal assault for beating ex-girlfriend Rihanna in 2009. If arrested again, Brown risks being jailed for probation violation.