Casey Johnson's Friend Vows To Watch Over Daughter Ava

Johnson & Johnson heiress Casey Johnson has died, leaving behind daughter Ava, whom she adopted from Kazakhstan in 2007.

The sad news was announced last night on Twitter by reality star Tila Tequila, who revealed in December that she and Casey were engaged.

"Everyone please pray 4 my Wifey Casey Johnson," Tila wrote. "She has passed away. Thank u for all ur love and support but I will be offline to be w/ family."

LA police later confirmed the report.

Model Jasmine Lennard tells Life & Style magazine today that she is "completely devastated" by her friend's death and vows to be a big part of Ava's life.

“Casey always made me promise if anything happened to her I would watch over her baby Ava, and with her family’s blessing I will honor that promise," Jasmine says.

“I will see Ava as soon and as much as possible, but I think it's very important to allow her family the time to grieve. I speak with Ava regularly on the telephone, but I don’t want her to be upset right now with the association of me and her mommy."

By all accounts the 30-year-old socialite, who is the daughter of New York Jets owner Robert Wood Johnson, led a troubled life, with a history of substance abuse and headline-grabbing stunts. Casey's mom Sale Johnson took custody of little Ava earlier this year out of concern for the toddler's safety, but recent reports indicated that Casey was trying to get her back.

According to police foul play is not suspected; a source tells People that Casey's death may have been the result of her neglecting to take her diabetes medicine.