Williams, who starred as Omar Little in the widely acclaimed television series, died of an accidental drug overdose in September.

The 54-year-old, who played the iconic Baltimore stick-up man in the groundbreaking show, was found dead in his apartment in New York.

The men have been charged with conspiracy to distribute the fentanyl-laced heroin that killed Williams, the US Attorney for the Southern District of New York said in a statement.

The prosecutor named the men as Irvin Cartagena, Hector Robles, Luis Cruz and Carlos Macci.

Cartagena allegedly sold the deadly dose, said attorney Damian Williams. He faces a mandatory minimum sentence of 20 years in prison and a maximum sentence of life if convicted.

The Emmy-nominated actor died from “acute intoxication by the combined effects of fentanyl, p-fluorofentanyl, heroin and cocaine,” New York’s chief medical examiner ruled.

Williams had been hailed for his role in “The Wire,” in which he played a gay armed robber who specialised in holding up drug dealers.

He was also well-known for the role of Albert ‘Chalky’ White on the HBO series “Boardwalk Empire.”

The actor had spoken openly of his past struggles with drug addiction and had told US media that he had spent much of his earnings from “The Wire” on narcotics.