Cause of Sean 'Diddy' Combs' Ex Kim Porter's Death Remains 'Complete Mystery'

The death of Kim Porter, Sean 'Diddy' Combs' ex-girlfriend and the mother-of-three of his children, has reportedly left investigators puzzled.

Sources told The Blast Friday that Porter's autopsy is expected to take place either today or Saturday. Investigators listed her preliminary cause of death as "natural" based on their interviews with friends and family and evidence from the scene.

Porter died Thursday at age 47, a few weeks after she reportedly suffered from pneumonia. A source also told TMZ that Porter spoke with her doctor on Wednesday to say she was not feeling better.

According to The Blast's sources, Porter was fighting the flu in the days before her death. She was seeing a private doctor, but investigators did not find any medications at the scene that could have led to an accidental death. In addition, investigators found Porter did not have a history of drug or alcohol abuse.

Porter's cause of death will remain deferred until toxicology test results are finalized.

Porter was found dead at her home in Toluca Lake, California. She was pronounced dead at 11:40 a.m. local time Thursday.

"Sadly, I can confirm the passing of Kim Porter. I ask that you give the families privacy at this time," Diddy's representative Cindi Berger said Thursday.

Porter and the music mogul dated for 13 years before their split in 2007. They had three children together, 20-year-old son Christian and 11-year-old twin daughters Jessie James and D'Lila Star. Combs has also helped raise Porter's son with Al B. Sure!, Star actor Quincy Brown.

Even after their split, the two appeared at public events together, including the October premiere for The Holiday Calendar, starring Quincy.

"Diddy is devastated and shocked. He and Kim were still very close friends and co-parents even though their romantic relationship didn't work," a source told PEOPLE. "They were still a family."

Following Porter's death, several celebrities took to Twitter to send their condolences to Combs and his family.

"The times spent with you and your family over the years will be treasured. Rest in power Kim Porter. My condolences to the Combs and Porter families," Lenny Kravitz wrote.

"My heart just aches so much 4 her children. She Loved them dearly she was proud of her kids & they Loved their mother so much. [Love] & Prayers for [Diddy] during such a difficult time," Missy Elliott wrote. "[Kim Porter] those that know you will always remember your SMILE your LAUGH & KIND HEART."

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