Abdul has worked as a judge on the show since 2002
American Idol judge Paula Abdul said she was "shocked and saddened" after a woman, who once appeared on the hit US TV show, was found dead.
Detective Robert Bub, of Los Angeles police, said he thought Paula Goodspeed had died of "suicide by overdose".
The 30-year-old was discovered in a car alongside prescription drugs, CDs and pictures of pop star Abdul. The car was found near the singer's home.
It is believed Goodspeed was an obsessed fan of the pop star.
'Heart and prayers'
Abdul said in a statement, released by her publicist Jeff Ballard: "I am deeply shocked and saddened at what transpired yesterday.
"My heart and prayers go out to her family."
An official cause of death has yet to be determined.
Police found Ms Goodspeed's body on Tuesday evening in a car with the licence plate ABL LV.
Ms Goodspeed sang the Tina Turner hit Proud Mary in her 2005 audition
Her parents had reported her missing hours earlier and expressed concern that she might hurt herself.
Ms Goodspeed auditioned on series five of American Idol, but failed to reach the next round after receiving poor reviews from Abdul and fellow American Idol judges, Randy Jackson and Simon Cowell.
She told the show's host, Ryan Seacrest, that she was a huge fan of Abdul and had created life-size paintings of the singer.
She also called Abdul "beautiful" after Cowell said he noticed a resemblance between Goodspeed and Abdul.