RIP Philip Seymour Hoffman; his death was an accidental overdose:

Philip Seymour Hoffman's sudden death this weekend (Feb. 2) is being treated as an accidental overdose.

A source close to the investigation tells FOX411. The source said Hoffman injected himself, but it is not believed he committed suicide.A rep for the medical examiner would not confirm the ruling, but said the 46-year-year-old actor's autopsy is being performed today.Police sources also tell Fox News they found considerable evidence of drug use in Hoffman's apartment, including 50 glassines -- small plastic bags -- some of which were empty, and many of which still contained drugs, used and unused hypodermic needles, and multiple prescription drugs.Hoffman's family has hired security around the apartment building he was living in to make sure no one can get inside, a source said.