In a bizarre real-life parallel, Stahl is now missing. While police continue their search for the 32-year-old actor, who was last seen on May 9, the director of 388 Arletta Avenue says he saw no signs of trouble when he shot the thriller with Stahl in Toronto a year and a half ago.
"He was fantastic – not a single problem," director Randall Cole tells PEOPLE. "He was a total professional and knew his lines. There was no diva behavior at all." Nor was there any hint of turmoil between Stahl and his wife Rose, who visited the set along with their then-infant daughter, Marlo. But court documents filed earlier this year tell a different story.
In February, Rose filed a petition calling for child support from her husband. Those papers also state that she would have their daughter 100 percent of the time and Stahl would have eight hours of supervised visitation per week. He was also required to take a drug test within 24 hours of each visitation.
Back in 2010, however, the couple "looked happy together," says Cole. "Whatever is going on now, it wasn't happening then. He was totally on his game. He is not an actor who stays in character between takes. He was just himself, goofing around with the crew. He was a pleasant person to be around."
Detectives have been searching for Stahl since the actor's wife, Rose, reported him missing to the Los Angeles Police Department Monday morning.
"We are tracking down a few leads and using internal sources with information we have to see if we can quickly locate him," L.A.P.D. Detective Carmine S. Sasso, who is handling the case, tells PEOPLE.
The actor, says Det. Sasso, "has got some personal issues that he's trying to work through. The family asks that this be kept very low-key, and that affects our ability to successfully solve these cases."
And what of reports that substance abuse issues are involved in Stahl's disappearance?
"In general, [this case] is similar to a lot of our adult missing persons cases," says Det. Sasso. "Of the 14,000 missing persons cases I've handled over the past four years, there's a very good percentage of those involving drug issues and a separation from families. The vast majority of them have been successfully solved. Hopefully this one will be too."
A Strange Limbo
Stahl, a Texas native who began acting at age 4 and got his big break in Mel Gibson's 1993 drama The Man Without a Face, has acknowledged past struggles with drugs and alcohol.
When another onetime child star, actor Brad Renfro, died from a heroin overdose at age 25 in 2008, Stahl said he had seen warning signs when the pair costarred in 2001's Bully.
"There was a lot of recreational drinking and things like that going on during the shoot," Stahl told The San Francisco Chronicle in 2008. "For someone like me, who has been through drugs and drinking, it was pretty easy to spot that Brad had problems."
Stahl also admitted that he had struggled as a child star.
"It warps your ability to find a certain identity," he said. "You are in a strange limbo. You are working in an adult world but being very young, you are not a part of it. You can't be included in it really. Then you go home and because you're with your friends not all that often, you're not fully a part of that, either."
And the glare of the spotlight didn't help.
"There are certain superficial elements of the business," he said, "kind of putting on a good face even though you might be in pain."