Actor Michael K. Williams, who as the rogue robber of drug dealers Omar Little on “The Wire” created one of the most popular characters in television in recent decades, died Monday, according to New York’s Amsterdam News.

Williams was found dead Monday afternoon in his Brooklyn penthouse apartment, New York City police said. He was 54.

His death was being investigated as a possible drug overdose.

Little, a “stick-up boy” based on real figures from Baltimore, was probably the most beloved character among the devoted fans of “The Wire,” the HBO show that ran from 2002 to 2008.

The Brooklyn-born Williams also appeared in numerous other shows and films for more than two decades, including roles on the HBO series “Boardwalk Empire” and and in the films “Bessie,” “12 Years a Slave,” “When They See Us,” and “Assassin’s Creed.”

In his most recent project, HBO’s sci-fi/horror series “Lovecraft County,” Williams played the alcoholic father, Montrose Freeman. Although the show was cancelled after one season, it received 18 Emmy nominations this year, including the one for Williams as outstanding supporting actor in a drama series.

Williams was open about his struggle with drugs over the years and spoke in various interviews about being addicted to cocaine while working on “The Wire.”

As Little, he played a criminal with a strict moral code, known for taking advantage of a reputation for brutality that wasn’t always real. He spoke many of the show’s most memorable lines, including, “a man gotta have a code” and “all in the game yo, all in the game.”

The character also broke TV ground as an openly gay man whose sexuality wasn’t central to his role.

Williams appeared in all five seasons of “The Wire,” his character growing in prominence with each season.

“Horrible, sad and unbelievable to think we’ve lost the fantastically talented Michael K. Williams at the age of 54,” tweeted writer Stephen King.