NEW YORK (NewsNation) — A criminal justice activist who recently appeared on Joe Rogan’s podcast has been arrested after a severed head was found in a freezer.

Sheldon Johnson, 48, was charged with murder, manslaughter, and criminal possession of a weapon, according to the NYPD.

While conducting a wellness check in the victim’s apartment at 979 Summit Ave. at around 8:30 p.m., police found the man’s torso with the legs attached, authorities and sources said. Collin Small, 44, was pronounced dead at the scene.

Johnson had become an advocate for prison rehabilitation after his release for a string of armed robberies in 1999.

His story of rehabilitation after his release from prison turned him into a criminal justice activist, and he made multiple public appearances. He spoke recently on “The Joe Rogan Experience” about his time behind bars.

“I got into school. I got my GED. From there, I got involved in correspondence courses,” said Johnson. “I started interacting with guys who were teaching aggression replacement training and I started to begin to understand how these concepts work. What positive visualization is. Deep breathing. Conflict resolution. All of these ideas of change began to take place with me.”

Queens Defenders, the nonprofit public law firm where Johnson worked, declined to comment.

Johnson is expected back in court Monday.

NewsNation affiliate WPIX in New York contributed to this report.