A spokesman for the family of New York Jets owner Woody Johnson, whose great-grandfather founded Johnson & Johnson, says a daughter of the businessman has died.

Spokesman Jesse Derris said Monday that the family is mourning the tragic loss of Casey Johnson.

In a statement, the family asked for privacy "during this very difficult time."

TMZ reported that the 30-year-old Johnson was found dead Monday in Los Angeles.

Casey Johnson had gained celebrity of her own as the girlfriend of television personality Tila Tequila.

In pictures: Tragic celebrity deaths of 2009

Tequila's publicist says the two were engaged to be married.

"Everyone please pray 4 my Wifey Casey Johnson. She has passed away," Tequila wrote on her Twitter account.

A second posting said: "This is a very heartbreaking time for me. I just want some pricacy (SIC) as I deal with the loss of my Fiance Casey Johnson. I'm (SIC) heart is shredded."

But shortly after, Tequila posted:"I just got news that my fiance is not dead but currently in a coma!!! Omg please pray that she will make it! Hang in there my love please!!!"

But a spokesperson for Los Angeles police confirmed to People magazine that Johnson was in fact dead.

"Police and firefighters were called to a house and Johnson was pronounced dead at the scene," officer Sara Faden said.

"It appears to be a natural death," the magazine quoted officer Faden as saying.

"There's no evidence of foul play. A toxicology report from the coroner's office will proceed next."

The lesbian reality star's latest posting seemed to accept the tragic death, "R.I.P my Angel. @caseyjonsonJnJ u will forever be in my heart! I love u so so much and we will Marry when I see U in Heaven my Wifey."

Gossip website TMZ reports Johnson had stayed with Tequila on December 28. But the pair fought and Johnson's phone had been off since the 29th.

The heiress announced her engagement to Tequila in December.

Johnson adopted a daughter named Ava from Kazakhstan in 2007 and was battling her mother, Sale Johnson, for custody of the girl.

Johnson had a reported history of drug use and failed at rehabilitation several times.

She was recently arrested for allegedly breaking into the Hollywood apartment of her ex-girlfriend, fashion model Jasmine Lennard.

Friends told the New York Daily News her father had cut off her trust fund because she was unable to sober up