In his book, A Cast of Killers, Stanley Kirkpatrick recounts an investigation into Taylor's death by fellow director King Vidor. I disremember many of the details, but Vidor concluded that Charlotte Shelby, Mary Miles Minter's mother, killed Vidor. Motive? Again, memory fades. Although gossip, encouraged by Paramount, linked Taylor & Minter romantically, in reality Taylor was homosexual. His houseboy often cruised nearby Westlake (now MacArthur) Park for you male hustlers.
Motive notwithstanding, Vidor believed Shelby bribed LA DA Burton Fitts to look the other way, thus the case remained unsolved. Because Fitts was still alive & known to be litigious, Vidor never published his findings.
His case against Shelby, as I recall, was pretty strong, if not conclusive.