5:20 PM PT -- Brian's rep, Laurie Smith, tells TMZ that she believes the actor died from complications due to a recent illness. Smith says Brian had been very sick for the past few months and was in upstate NY for about a month being treated for a possible heart issue.
Smith adds ... Brian was recently released from the hospital, but after speaking to him a couple days ago, she says she learned he suffered another setback. Because of this, she believes his death is tied to his ailing health.
Brian Tarantina has died ... TMZ has learned.
Law enforcement sources tell us that the veteran actor was found dead early Saturday morning in his Manhattan apartment from what we're told appeared to be a fatal drug overdose to the officers and first-responders who came out.
Our sources say Brian's niece went to check in on him at his Hell's Kitchen residence at around 12:30 AM, and discovered her uncle unresponsive on the couch. We're told the niece told cops she'd last talked to him late Tuesday night. Upon finding him, she called 911, and we're told when officers and paramedics arrived ... they found a white powdery substance near his body, believed to be alleged narcotics. He was pronounced dead on the scene.
It's unclear at this point what the white substance might've been. We're told the NYC medical examiner's office will conduct an autopsy to determine an official cause of death.
Brian has been working in the biz for a long time, often playing supporting characters through the '80s and '90s, and even into the 2000s and onward. He's perhaps best known for tough guy roles in flicks like "Jacob's Ladder," "Uncle Buck," "The Jerky Boys," "Summer of Sam," "Knight and Day," "Carlito's Way," "Donnie Brasco," "City By the Sea" and others.
He's got a much more extensive resume than that though. The guy's been in tons of stuff over the years ... shows like "Law & Order," "Miami Vice," "Spin City," "Oz," "NYPD Blue," "ER," "The Sopranos," "Gilmore Girls," "Heroes," "The Black Donnellys," "The Blacklist," "Madame Secretary," "Blue Bloods" and most recently in "The Marvelous Mrs. Maisel" playing Jackie.