`` Bonanza '' star 's son Mark Landon found dead in West Hollywood home . The Los Angeles County coroner ruled the death a suicide, but police said they are investigating whether it was an accident or murder. He is best known for his 14 years as `` Little Joe '' Cartwright in TV 's long-running `` Bonanza , '' and later as Charles Ingalls in nine seasons of `` Little House on the Prairie . '' Mark Landon had a few acting credits , playing small roles in three movies .
`` Bonanza '' star 's son Mark Landon found dead in West Hollywood home . The Los Angeles County coroner ruled the death a suicide, but police said they are investigating whether it was an accident or murder. Mark Landon had a few acting credits , playing small roles in three movies .