Stahl's estranged wife, Rose Murphy, reported the film star missing Monday, telling police she has not seen the father of her toddler-age daughter since May 9.
Murphy also said the 32-year-old star of "Terminator: Rise of the Machines," "In the Bedroom" and "Sin City" had been using drugs and hanging out on skid row.
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.
E! News quoted an unidentified source, who allegedly saw Stahl May 10, as saying the actor is known to go missing and his absence isn't necessarily a cause for alarm.
"He does this sometimes," the insider told E! News. "He'll be back."