After decades of sobriety, Oscar-winning actor Philip Seymour Hoffman, 46, loses his long battle with drug addiction on Feb. 2, leaving behind three young children and a lasting legacy on screen and stage. In this week’s issue of PEOPLE, his shattered friends and family search for answers.

Hoffman was a star with scene-stealing roles in more than 50 films, but in the downtown Manhattan neighborhood he had called home for years, he was simply one of the locals. Still, as expert as he was at blending in, he did draw attention when he turned up at the Barrow Street Alehouse after returning from a 10-day detox for heroin addiction last spring. “I remember he had just gotten back from rehab, and he ordered one half of a beer,” recalls a neighborhood friend.

“The bartender said, ‘Phil, a beer is three bucks. You can’t splurge for a whole?’ Then it hit us that he was trying not to drink by drinking only ‘half.’ But that’s not how it works, unfortunately. He just couldn’t fight the demon.”

Found unconscious in the bathroom of his rented fourth-floor apartment by a friend, Hoffman died of an apparent drug overdose, with police officials confirming he had a syringe still inserted in his left arm. While authorities continue to investigate the source of the heroin, Hoffman’s family and friends were left reeling. “My heart is torn asunder for Mimi and their kids,” says Hoffman’s friend Adam Nelson, referring to the actor’s longtime girlfriend Mimi O’Donnell, 46. “Phil was starlight. The gold standard.”

He was also troubled. Locals in his West Village neighborhood observed the actor during both happy and seemingly darker moments. “He’d go over to Oliver’s restaurant with his son Cooper. They’d have lunch, and you’d see them talking and laughing for hours at a time,” says the neighborhood source. “Then, come nightfall, you’d see Phil back at Oliver’s, hunched over the bar, alone, looking like an entirely different man. He looked very dark and depressed.” A second source says he witnessed Hoffman stumble into his apartment after late nights out, “needing to be helped into the building.”

Just the night before his body was found, he was spotted at neighborhood restaurant, Automatic Slim’s, where he and two friends dined on guacamole and burgers. His friend had a beer; Hoffman drank only a cranberry soda. According to the bartender, “He seemed fine.”

Last May he shocked many in Hollywood when he revealed that after 23 years of sobriety, he had fallen into heroin addiction after first using prescription drugs. He spent just 10 days in a detox program before resuming a busy shooting schedule that included roles in a now-defunct Showtime pilot and the final two installments of the blockbuster Hunger Games franchise.

Deeply committed to his children, Hoffman was a fixture at the Chelsea Piers athletic complex in NYC, where he turned up every Saturday for his son Cooper’s basketball practices. “He was not a drop-off parent,” says Ryan Berger, a fellow dad who had seen him just 24 hours before his death. “He was committed to what his son was doing.” Now, as those who loved Hoffman say goodbye and those who admired his work mourn what might have been, there is only sadness at the loss of a “really bright person, a family man who made so many good choices,” says Matthew Warchus, who directed his Tony-nominated turn in 2000’s True West.

“That’s the hideous part about addiction.” Adds Michael Ohoven, producer of the film Capote, for which Hoffman won his Oscar: “For somebody so intelligent and with enormous willpower to succumb to such a terrible disease, I can’t even grasp it. All I can think about is that he’s sitting up there and giving one of his dark, big chuckles.”

More on Philip Seymour Hoffman is featured in the 2.17.14 issue of PEOPLE, on newsstands now.

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