Police Raid at Charlie Sheen's House

Sources tell us the LAPD has been conducting an investigation into criminal activity -- possibly drugs or weapons. And someone who is at the house tells us cops may be attempting to put Charlie on an involuntary -- 5150 -- psychiatric hold.

UPDATE: Someone at the house tells us, one of the reasons the cops are there is because Charlie allegedly violated the temporary restraining order Brooke Mueller obtained ... which prohibits Charlie from possessing weapons.