The NYPD has reportedly launched an investigation into the death of actor Michael K. Williams.

TMZ reported NYPD investigators are looking for the drug dealer who sold Williams the narcotics found in his Brooklyn apartment.

Williams was found

dead in his home on Monday, as previously reported. His nephew discovered his body while doing a welfare check because he hadn’t heard from The Wire actor in a few days. A cause of death has not been determined, but authorities suspect a heroin overdose. He was 54 years old.

The sudden loss has led to an outpouring of love for Williams and his iconic career. Several celebrities have paid their respects to the Lovecraft Country star.

“You, brother, touched many. Through your personal interactions, big and small, through your community activism, through your struggles, through your triumphs, through your glorious work. You moved many,” When They See Us director Ava DuVernay wrote in a heartfelt Instagram post. Williams portrayed Bobby McCray, Central Park 5 member Antron McCray’s father, in the film. “You moved me. What you doubted in life, be certain of now, dear brother. Be certain. You were a flash of love – now gone. But never forgotten.”

“If you don’t know, you better ask somebody. His name was Michael K. Williams. He shared with me his secret fears then stepped out into his acting with true courage, acting in the face of fear, not in the absence of it. It took me years to learn what Michael had in abundance,” Wendell Pierce, Williams’ former co-star on The Wire

, tweeted.

On Thursday, New York Assemblywoman Rodneyse Bichotte Hermelyn announced an upcoming criminal justice reform bill named after Williams. Hermelyn is working with the American Civil Liberties Union on legislation aimed at decreasing New York’s prison population. Williams had worked with ACLU as an ambassador for ending mass incarceration.

“The Michael K. Williams bill will serve to reduce mass incarceration, which disproportionately hurts people of color and costs taxpayers millions of dollars,” Hermelyn told The New York Post in a statement.

“This was Michael’s mission, and in New York State, we can and must do better,” the assemblywoman added. “We will keep our communities safe and reduce racist policies that have led to America’s for-profit criminal justice system.”