Marilyn Monroe's iconic career has left a lasting legacy in Hollywood, but the final moments of her life were nothing short of tragic.

While the actress, born Norma Jeane Mortenson, captured the hearts of millions throughout her short time in the spotlight, behind the scenes, she was suffering. In 1961, she spent time in a psychiatric clinic, which had a "very bad effect" on her.

The last day of Monroe's life, Aug. 4, 1962, is still shrouded in mystery. At the time, Monroe was under the constant care of a doctor and psychiatrist, who had prescribed her numerous medications to treat mental health issues as well as her insomnia. Unfortunately, despite the efforts to care for the starlet, she overdosed on prescription medication, ending her life far too soon.

So what happened to Marilyn Monroe? Here are all the details of her sudden passing

Monroe's death was ruled an overdose and "probable suicide." According to the coroner's toxicology report, the official cause of death was acute barbiturate poisoning. The toxicologist determined that Monroe ingested a lethal dose of Nembutal, a drug that is used to treat anxiety, as well as a large dose of chloral hydrate, a drug used as a sedative.

Despite Monroe's death being ruled an overdose, mysterious circumstances surrounding her passing have fostered conspiracy theories that foul play was involved. Questions have been raised regarding Monroe's involvement with the Kennedy family, as she was rumored to be having an affair with both President John F. Kennedy and his brother, Attorney General Robert F. Kennedy — who some say visited her the night of her passing. Some investigators have gone as far as to suggest the CIA was involved in her death. Others have questioned why hours elapsed before her body was turned over to medical examiners and the whereabouts of not-yet-tested tissue samples.

The controversy surrounding Monroe's passing was so intense that the Los Angeles Police Department reopened her case two decades after her death. Although there was further investigation, the district attorney found that her death was still ruled a drug overdose. Shortly after, journalist Anthony Summers conducted his own investigation which resulted in 650 tape-recorded interviews, which were eventually released to the public in The Mystery of Marilyn Monroe: The Unheard Tapes.

"There is no good evidence she was murdered," says Summers told PEOPLE. "I think it's more likely—whether as a cry for help or intending suicide—she took too many pills."

Monroe is presumed to have passed away on Aug. 4, 1962, in the late hours of the evening. However, her official time of death was 3:50 a.m. on Aug. 5, 1962.

She was found unresponsive in her bedroom at her home in Brentwood, California. At the time, Eunice Murray, her housekeeper, was on the property and grew concerned when she noticed Monroe's bedroom light was on in the early hours of the morning on Aug. 5.

When Monroe did not answer Murray's calls and she discovered the bedroom door was locked, the housekeeper alerted Monroe's psychiatrist, Dr. Ralph Greenson. Around 3:30 a.m., he broke into the room through a window. The movie star was found nude and face down on her bed with a telephone in one hand. Empty pill bottles were scattered around the room.

The actress was 36 years old at the time of her passing.

According to Summer, one of Monroe's last phone conversations occurred with her hairdresser, Sydney Guilaroff, at 9:30 p.m. on Aug. 4. The actress reportedly told Guilaroff that Bobby Kennedy had come to her home earlier in the day and "threatened" her. However, Kennedy's visit has been disputed as Attorney John Bates told reporters that the Attorney General was in Northern California with his family the entire weekend.

Peter Lawford, an actor who was married to socialite and Kennedy sister Pat Lawford, also allegedly spoke to Monroe on Aug. 4. The actor invited Monroe to join the couple for dinner and when Monroe did not arrive, he called her again, explaining that she was "despondent" about career and personal issues.

Lawford says that in "slurred" speech Monroe told him she was "tired and would not be coming" to dinner. Then, as her voice became less audible, she told him, "Say goodbye to Pat. Say goodbye to Jack [President Kennedy]. And say goodbye to yourself, because you're a nice guy."

The actor later admitted he had a "gut feeling" that something was wrong and that "he still blames himself for not going to her home himself," according to a police report.

The public was devastated by the death of the iconic actress, with the news of her passing making the front page of newspapers around the world.

Ahead of her funeral at Westwood Village Memorial Park Cemetery on Aug. 8, her ex-husband Joe DiMaggio, half-sister Berniece Baker Miracle and business manager Inez Melson released the following statement: "We sincerely hope that the many friends of Marilyn will understand that we are deeply appreciative of their desire to pay last respects to Marilyn whom we all loved.

They continued, "We hope that each person will understand that last rites must of great necessity be as private as possible so that she can go to her final resting place in the quiet she has always sought. We could not in conscience ask one personality to attend without perhaps offending many, many others and for this reason alone, we have kept the number of persons to a minimum. Please — all of you — remember the gay, sweet Marilyn and say a prayer of farewell within the confines of your home or your church."

Monroe is widely considered one of the greatest sex symbols of the 20th century. Even 60 years after her passing, she is still highly regarded in the entertainment industry — inspiring movies and documentaries. Her beauty and glamour remain an important part of pop culture and her image can often be found in apparel, posters and other merchandise.