Academy Award-winning actor Philip Seymour Hoffman was found dead in his New York City apartment on Sunday, according to the New York City Police Department.
Hoffman's body was discovered Sunday at his home in the West Village.
Sources say two friends found Hoffman in the bathroom with a needle in his arm.
Authorities tell NY1 that police found eight empty glassines and two glassines allegedly containing heroin.
In a statement, Hoffman's family said, "We are devastated by the loss of our beloved Phil and appreciate the outpouring of love and support we have received from everyone. This is a tragic and sudden loss and we ask that you respect our privacy during this time of grieving. Please keep Phil in your thoughts and prayers."
Mayor Bill de Blasio tweeted a statement as well.
"Saddened by Philip Seymour Hoffman's tragic and untimely passing. Today New York mourns the loss of one of stage and screen's greats," reads the mayor's tweet.
As authorities investigated Hoffman's death, they had to keep a growing crowd of onlookers back.
New Yorkers assembled outside the 46-year-old's West Village apartment as the news spread through the city streets.
Some were visibly upset, and all felt the loss as they remembered their private, unassuming neighbor.
"Just sad. Such a waste of a great talent," said one person.
"He's one of the nicest guys you'd ever met," said another. "Always friendly, always looking out for everybody."
"Very, very quiet, nice, polite," said a third. "Never make any noise. Never complain about anything."
Hoffman gained recognition as a character actor, appearing in such films as "The Big Lebowski," "Almost Famous," "Magnolia" and "Twister."
"He's one of the few actors of our generation who I would call a great actor, a brilliant actor who could just embody any part so that all you could see was the character," said one person.
The medical examiner's office removed Hoffman's body Sunday evening as a memorial grew outside his apartment and in nearby restaurants.
NY1 is told that the West Village fixture spent his final hours having a casual burger dinner - no drinks - with two friends at a nearby restaurant.
"The bartender saw him last night," said one person. "He came here and ate."
In the past, Hoffman spoke candidly about his struggles with addiction.
"I heard he had relapsed recently. He was having trouble, so it wasn't a total shock," said one person. "But it's a sad thing. He was a great talent."
A native of Fairport, N.Y., Mr. Hoffman, 46, won the Academy Award for Best Actor for the 2005 film "Capote."
He was nominated three more times, most recently for director P.T. Anderson's 2013 film "The Master," where Hoffman played a charismatic cult leader.
The two other Oscar nominations were for his work alongside Tom Hanks in "Charlie Wilson's War," and in 2009, where he played a Catholic school priest accused of sexual abuse in the movie "Doubt."
On stage, critics and audiences raved about his portrayal of Willie Loman in the 2012 Broadway revival of Arthur Miller's "Death of a Salesman," a role that earned him his third Tony nomination.
In 2010, he tried his hand at directing with the film "Jack Goes Boating."
Hoffman appeared last summer in the blockbuster "The Hunger Games: Catching Fire." He was currently filming the next installments of the popular film series.
He leaves behind three kids he had with longtime girlfriend Mimi O'Donnell.