(NewsNation) — The junior coroner who performed the autopsy of Marilyn Monroe still has his doubts over the circumstances of her death, 63 years on.
Monroe died Aug. 4, 1962, at the age of 36. Evidence has long pointed to suicide, but some have their doubts.
Coroner Thomas Noguchi, 98, performed the autopsy and told author Anne Soon Choi, in her book L.A. Coroner, he felt “alarm bells going off on his head” when the head toxicologist refused to run additional tests.
Marilyn Monroe reportedly took sleeping pills
Choi said “a wave of anxiety” washed over Noguchi, via the Daily Mail. According to the author, he was never able to fully free himself from doubts over what really may have happened to Monroe.
Following Monroe’s death, the public was told Monroe died at her own hand via the ingestion of sleeping pills.
“When he does the evisceration of her body, that’s the removal of the organs; he found nothing in her stomach, and there’s no corollary between that relative to the ingestion of pills and what you’re going to get back on the toxicology report,” forensic analyst Joseph Scott Morgan told “Banfield.”
Marilyn Monroe leaves the home she briefly shared with Joe Di Maggio in a car driven by her attorney, Jerry Giesler. Monroe had just announced her intent to divorce Di Maggio on grounds of “mental cruelty”. (Getty Images) 
1954: American film star Marilyn Monroe (1926-1962). (Photo by Baron/Hulton Archive/Getty Images) 
People visit and photograph the ‘Forever Marilyn’ statue of actress Marilyn Monroe in Palm Springs, California, on August 4, 2012, a day ahead of the 50th anniversary of Monroe’s mysterious death. (Frederic J. Brown/AFP via Getty Images)
“Because her levels were blown through the roof. As a matter of fact, they’re described in terms of being lethal levels. And it’s kind of a fascinating dynamic. How are the drugs delivered into her system?”
Morgan made mention of speculation that Monroe may not have killed herself and instead administered a lethal suppository, given there were no injection marks found on her body.
“My suspicion is that Marilyn Monroe’s death will forever remain shrouded in mystery and plus, it’s great talk for people to continue on about for years and years after the fact,” he added.
Marilyn Monroe death conspiracies
Rumors have swirled for decades over the actresses death, whether it was suicide, accident, or she was killed.
According to the Los Angeles Times, some people believed she was killed over her connections to President John F. Kennedy and then-U.S. Attorney General Robert F. Kennedy.
The FBI’s files on Monroe showed that the bureau looked into different theories about her death, the LA Times reported.