After news broke of his sudden death yesterday (Feb. 2), Oscar-winning actor Philip Seymour Hoffman's passing is being treated as an accidental overdose.

A source close to the situation says this will be either confirmed or denied when an autopsy is performed today.

The actor was found dead on his bathroom floor with a needle in his arm in a rental apartment after reportedly separating from his partner of 15 years, Mimi O'Donnell.

In addition to the needle, police also located 50 empty glassines (tiny plastic bags), not all of which were empty, hypodermic needles (both used and unused) and a variety of prescription medication in the apartment.

Even more heartbreaking, on the day of his death, Hoffman reportedly had plans to spend the entire day with his children. In particular, he was going to watch the Super Bowl with his son.

When he never showed to pick up his three kids (son Cooper and daughters Tallulah and Willa), family and friends became worried as the move was very "uncharacteristic of him."

His friend (and playwright) David Bar Katz went to check on the Academy Award winner, only to find the actor dead on the floor.

"I saw him last week, and he was clean and sober, his old self," Katz told the New York Times. "I  really thought this chapter was over."

In addition to following various leads about where Hoffman might have bought drugs in the area, police are also trying to determine whether or not the actor injected a deadly batch of heroin which is responsible for hundreds of recent deaths around the country.

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