"He could have overdosed, that's one thought. And I'm wondering if there will be a body recovered," Rose Murphy told People magazine.
Murphy reported Stahl missing May 14 after he disappeared May 9 when his roommate took a break during their morning meditation session, People reported Friday.
Stahl had been living separately from Murphy since February after a court filing prevented the actor from seeing the couple's 2-year-old daughter if he fails a drug test. Murphy said the separation did not indicate the marriage was over.
"That was an adult, loving decision that we made to try to inspire his recovery and maybe even scare him away from relapse," she said.
Murphy told People that as Stahl has worked through his recovery, he has disappeared a few times, but only for one to four days at a time.
Los Angeles Police Department spokesman Richard French told the Los Angeles Times officers working the city's downtown drug district are looking for Stahl and foul play is not suspected at this time. Officers in the city's downtown skid row neighborhood have been told to keep an eye out for the actor.