In 1982, Van de Kamp assigned Carroll to conduct a "threshold inquiry" to determine whether a full-scale homicide investigation of Monroe's death was justified.
The 36-year-old Hollywood sex symbol was found dead and naked on her bed in her Brentwood home on Aug. 5, 1962. As the 20th anniversary of her death approached, numerous assertions that the actress may have been the victim of foul play spurred the district attorney's 3 1/2-month inquiry.
The 30-page report, prepared by Carroll and investigator Alan B. Tomich, concluded: "Our inquiries and document examination uncovered no credible evidence supporting a murder theory."
And, The Times reported in 1982, the report "concluded that there was 'reasonable' evidence to support a coroner's finding 20 years earlier that Monroe's death from a barbiturate overdose was probably a suicide."
Van de Kamp, The Times reported, had "made the assignment public after the Board of Supervisors urged him to investigate new charges by a former county coroner's employee that a diary purportedly kept by Monroe had disappeared from the coroner's office."
The Times reported that the former employee, Lionel Grandison, said the diary contained the names of government figures and possibly matters relating to sensitive government operations.
But Carroll said he did not find any credible evidence that the coroner's office was ever in possession of a diary, The Times reported, and "Carroll concluded that a murder of Monroe fitting the known facts of her death would have required a massive conspiracy."