Philip Seymour Hoffman -- Cops Want Video of Possible Drug Deal

Philip Seymour Hoffman may have been videotaped buying drugs the night before he died ... and now cops are working to get their hands on it ... and there are 2 mysterious men who may have been with Hoffman.

Hoffman was allegedly spotted by a man who claims he saw Philip withdraw large amounts of money from an ATM near the apartment where he was found dead ... according to Fox411.

The witness says he saw PSH hand over the cash to two men with messenger bags strapped to their bodies -- something typically worn by delivery drug dealers on the East Coast. The witness says he saw what he believed to be a drug deal.