The Kiss Kiss hitmaker's house in California's San Fernando Valley was raided by thieves who made off with money and other belongings after forcing the star's aunt into a closet.

Sources tell TMZ.com that Brown has now stepped up security at the mansion, adding two guards on a 24-hour watch to the perimeter of his home.

The insider suggests that the singer has also decided to limit the number of guests he allows in his home in a bid to tighten security there.