"But then he called her back like 20 minutes later and told her he was 'all Gucci' and couldn't pick up because he was talking to the cops," added the source.
"After Rihanna talked to him, she took a deep breath and told him to 'be careful.' She asked if he needed anything, but he said 'he had everything under control'. That scared her though," said the source.
Brown, 23, has blamed paparazzi for causing him to lose control of his Porsche, but they deny the accusation.