Angelo Bertolotti never stopped wondering what really happened to his daughter.

Brittany Murphy, the Hollywood actress whose breakout role was 1995’s teen comedy “Clueless,” died suddenly in 2009 at age 32.

Ed Winter, an assistant chief coroner in Los Angeles County, told The Associated Press that the star had collapsed in the bathroom of the Hollywood Hills home she shared with her husband, British screenwriter Simon Monjack.

In 2010, just five months after Murphy’s passing, Monjack was also found dead in the couple’s home at age 40.

The star is now the subject of a new Investigation Discovery (ID) documentary titled “Brittany Murphy: An ID Mystery,” which revisits the shocking case. The special is part of “ID Presents: Nine at 9,” which offers new shows running nightly on the true-crime network.

JEFFREY DAHMER WITNESS SAYS SHE SAW 'A STREAK OF EVIL' WHILE TRYING TO RESCUE VICTIM FROM GRISLY FATE: DOC

LORENA BOBBITT ON REVISITING HER NOTORIOUS CASE IN LIFETIME FILM: 'THERE WAS A LOT OF TRAUMA'

It also features Bertolotti’s final interview before his death in 2019 at age 92. The patriarch had previously cast doubt on the conclusion that his famous daughter died of natural causes. Forensic pathologist Dr. Cyril Wecht, who was brought in by Bertolotti to investigate Murphy’s mysterious death, also participated in the documentary.

“He was very persistent in wanting to find out what happened to his daughter,” Wecht told Fox News. “It had even reached the point we were talking about excavation. Unfortunately, he did not have power of attorney and there was no legal way in which he could have accomplished that. There was no kind of criminal investigation and nobody was requesting it.”

Wecht admitted he was just as perplexed by Murphy’s sudden demise and was eager to investigate what could have really happened.

“What stood out to me was that here’s a young woman of 32 years old,” he explained. “How could she have developed such an advanced state pneumonia and such an incredible state of iron deficiency? Where in the world was her mother, her husband? Why didn’t she receive proper medical care? I was just puzzled by all of it. She had the financial means to see a doctor. And then she had prescriptions to strong opiates. It was very perplexing.”

ANGEL'S LANDING SURVIVOR RECALLS ESCAPING DEADLY CULT IN NEW DOC: ‘IT DIDN’T TAKE LONG FOR THINGS TO TURN’

Actress Brittany Murphy attends the Los Angeles premiere for 'Across The Hall' at Laemmle's Music Hall 3 on December 1, 2009 in Beverly Hills, California.  (Photo by Brian To/FilmMagic/Getty)

DETECTIVE RECALLS MEETING ‘TRUCK STOP KILLER’ BRUCE MENDENHALL IN ‘DEADLY RECALL’: ‘THERE’S EVIL OUT THERE’

A lab report commissioned by Bertolotti showed the alarming presence of 10 potentially toxic heavy metals from a hair strand sample. It suggested that there was a possiblility Murphy didn’t die from natural causes but instead was poisoned.

L.A. county assistant chief coroner Ed Winter, who also participated in the documentary, previously told E! News he was aware of the independent lab testing, but said the metals present were due to Murphy coloring her hair.

“She wasn’t poisoned, and we stand by the cause of death,” he told the outlet. “She died from over-the-counter medicines, pneumonia and anemia.”

Wecht said the findings of heavy metals should have been further investigated, as they “certainly could lead to problems.”

AL CAPONE’S GRANDNIECE REACTS TO TOM HARDY’S TRANSFORMATION IN NEW TRAILER FOR BIOPIC

Simon Monjack and Brittany Murphy attend the 2007 Award of Hope Gala Honoring Michael Ball of Rock & Republic with Performance by John Legend at Four Seasons Hotel on June 9, 2007 in Los Angeles, CA. (Photo by ANDREAS BRANCH/Patrick McMullan via Getty Images)

OWNERS OF LATE CHILD STAR JUDITH BARSI’S HOME SAY THEY FELT ‘A DARK PRESENCE’ IN ‘MURDER HOUSE FLIP’

“Absolutely,” he said. “They don’t cause pneumonia, but they can produce all kinds of problems… Where would you get 10 heavy metals and why would you use them? She did dye her hair, but I don’t know if that was ever followed up in a scientific fashion, to get the hair dyes she died and have them chemically analyzed to confirm that. That’s not hard to do. That’s the kind of study that should have been done. But to my knowledge, it was never done.”

Is it impossible to rule out murder? Wecht said that’s hard to say.

“Yes, I would say that it’s impossible,” he explained. “But impossible is a strong word that I don’t like to use without absolute certainty. The one thing that is absolute in science and in forensic science is cellular DNA. I can’t rule out the impossibility, but I stand by what I said. Take into consideration how someone would have gained access to 10 different heavy metals. How would you put them together? Why were 10 put together instead of one or two? How did they get there? And it takes time to build up heavy metals in hair. It doesn’t just happen with one dose.”

“I can only say what I’ve said before -- it’s not possible to completely rule out things,” he continued. “But you have to deal with the questions - questions that I feel were never truly answered.”

'FAMILIES OF THE MAFIA' STAR KAREN GRAVANO EXPLAINS WHY DAD SAMMY ‘THE BULL’ IS APPEARING ON MTV REALITY SHOW

Brittany Murphy during the New York premiere for "Little Black Book." (Photo by James Devaney/WireImage/Getty)

KIM KARDASHIAN DETAILS HER NEW DOC, SAYS SHE'S NOT WORRIED ABOUT JUSTICE REFORM CRITICS

Bertolotti, who was estranged from Murphy and his ex-wife, never got the answers he sought. In late 2013, Sharon Murphy wrote a letter to The Hollywood Reporter, hitting back at his allegations of a potential homicide.

“His claims are based on the most flimsy of evidence and are more of an insult than an insight into what really happened,” she wrote, as reported by E! News.

The Associated Press also said that a report from the coroner’s office showed that multiple drug intoxication, all prescription medications, contributed to Murphy’s death.

“[Brittany and Simon] both had similar causes of death,” Winter told E! News. “Brittany had an overdose of over-the-counter meds along with pneumonia and anemia, and Simon died of, again, pneumonia… and his overdose was from prescription meds.”

‘FORGOTTEN WEST MEMPHIS THREE’ DOC AIMS TO GIVE VICTIMS OF NOTORIOUS CRIME 'THEIR VOICES BACK,’ HOST SAYS

Brittany Murphy played Tai Frasier in 'Clueless.' (Photo by CBS via Getty Images)

PRINCE ANDREW ACCUSER VIRGINIA ROBERTS GIUFFRE TO STAR IN NETFLIX DOC ABOUT JEFFREY EPSTEIN

“I think it could have been preventable,” he shared. “The problem is Simon would doctor shop and got numerous medications with numerous names and had a problem with prescription meds. Brittany was sick and instead of getting her treatment, Simon and her mother didn’t take her to the doctor and used an abundance of over-the-counter meds. My feeling [is] it was inevitable that [Simon] was at some point going to die either because of overusing or his body couldn’t take it anymore.”

There will always be questions surrounding Murphy’s final days. The outlet noted that while Sharon alleged she hadn’t been informed about the possibility of toxic mold being present in the mansion, no evidence of the effects of a mold infection was found in Murphy’s body by the coroner. However, the results of any environmental reviews of the property have never been made public either.

The outlet also shared that the LAPD never treated the house as a crime scene. Therefore, there is “no verifiable accounting” of any chemicals or agents, poisonous or not, present in the house at the time of Murphy’s death.

For Wecht, the case will never truly be clarified in the years ahead.

GREEN RIVER KILLER GARY RIDGWAY IS STILL HIDING MANY 'DARK SECRETS' DESPITE CONFESSION, SAYS PROSECUTOR IN DOCUMENTARY

American actress Brittany Murphy poses on December 11, 2006 in Sydney, Australia. (Photo by Toby Zerna/Newspix/Getty Images)

TED BUNDY’S EX-GIRLFRIEND RECALLS HER RELATIONSHIP WITH THE SERIAL KILLER IN DOC: ‘I WAS DEVASTATED’

“The body has undergone extensive decomposition at this point,” he said. “Now it's all over. There's no way meaningful scientific studies can be done. But there’s no question about the pneumonia. This was shown and proven. There’s no question at all about the advanced pneumonia or the iron deficiency. That cannot be avoided… Still, it’s all too late now.”

“Brittany Murphy: An ID Mystery” airs Tuesday, May 26th at 9 p.m. EST on ID. The Associated Press contributed to this report.