Why actress Lisa Robin Kelly died in an addiction rehab center last week will not be known for another two months, a coroner's office spokeswoman said Sunday.
The autopsy on Kelly, one of the stars of TV's "That '70s Show," was completed Saturday, but it will be another eight to 10 weeks before toxicology results are back from the lab, according to Los Angeles County Coroner Lt. Cheryl MacWillie.
"Lisa had voluntarily checked herself into a treatment facility early this week where she was battling the addiction problems that have plagued her these past few years," agent Craig Wyckoff told CNN on Thursday. "I spoke to her on Monday and she was hopeful and confident, looking forward to putting this part of her life behind her."
She died late Wednesday in a Los Angeles area treatment facility, he said.
Kelly, 43, played Laurie Forman -- older sister of Eric Forman, played by actor Topher Grace -- on "That '70s Show," which ran from 1998 to 2006.