The article contains major SPOILERS for 9-1-1 season 6, episode 12.9-1-1 star Peter Krause addresses Wendell's death in season 6. Before 9-1-1 took an extended break late last year, the police drama left on a note of mystery and loss as Bobby (Krause) discovered the remains of his sponsor, Wendell (Maurice J. Irvin), and came to suspect that Wendell's passing isn't accidental. In the most recent episode, it's revealed that Wendell was working to expose the abusive patterns of Winding Path when he received a lethal injection that ended his life. Fortunately, a hidden camera was installed in the room where it all happened.
https://screenrant.com/911-season-6-wendell-death-bobby-actor-response/