Hendrix whose manager Mike Jeffreys was MI5 or MI6 possible waterboarded Jimi with red wine. Hendrix was singing about the emancipation of woman and other politically sensitive issues. Died of a drug overdose.
Janis, Richard Prior, Tupac, all brought down in some ways mostly due to OD.
This stuff goes deep. There are CIA, Stanford U, MKUltra, Navy Intelligence connections with so many in the entertainment world. Laurel Canyon (Steve Stills, Zappa, Manson, etc) all tied in with possible mind control experiments.