Porter, who dated the rapper for 13 years before breaking up in 2007, was found dead on Thursday in her Toluca Lake, CA home.
LAPD Officer Jeff Lee confirmed to Radar, "An investigation is underway at Kim Porter's address. That call came out at 11:38 this morning. And there is a female deceased at the scene. We are sending our homicide detectives over there to find out whether or not foul play was involved."
A rep for Porter also confirmed her death to Radar. "Sadly, I can confirm the passing of Kim Porter. I ask that you give the families privacy at this time."
According to an emergency dispatch called, Porter suffered "cardiac arrest."
Although she'd reportedly been suffering a bout of pneumonia over the last couple weeks, the exact cause of her death is unknown at this time.
Porter's aunt Georgina Green told Radar the family has "no idea" what happened to the model mom.
"We don't even know what happened," she said. "Kim was wonderful."
Porter and Diddy have a son, Christian Combs, and twin daughters Jessie James and D'Lila, who were born in 2006.
The model and actress also has a son named Quincy from her previous relationship with Al B. Sure!.
We pay for juicy info! Do you have a story for RadarOnline.com? Email us at email@example.com, or call us at (866) ON-RADAR (667-2327) any time, day or night.