Chris Brown has gone radio silent when it comes to helping cops track down the thugs who busted into his house and robbed him over the summer.
Law enforcement sources tell us the investigation into the July robbery at Chris' house has stalled out ... mostly because the singer is dragging his feet on answering questions the LAPD detectives need answered to go forward.
You'll recall ... 4 people stormed the house, held his aunt captive at gunpoint and then made off with cash and other items. We're told Brown still hasn't provided any details about what was taken. As TMZ first reported, multiple sources connected to Brown and the investigation tell us the perps were tight with Brown.
We're told the best lead cops still have are fingerprints off an item the suspects dropped while fleeing, but they haven't found a match yet.