"He's been missing for four days," Stahl's wife, Rose Murphy Stahl, confirms to E! News. "But I don't want to comment any further."
After checking out of rehab last weekend, Nick went to stay at a friend's house. He was then seen in downtown Los Angeles, but the source says that after that, he returned back to his friends.
He has not been spotted since he left a friend's house on Thursday night.
The source tells E! News: "Now he's disappeared. We can't find him anywhere. He has not made contact with anyone. We are all just desperately looking for him."
Search efforts have so far proved futile. "Everyone just wants him to come home," the source adds. "It's a terrible situation. We are searching, but we've had no solid leads."
Stahl first went missing in May but surfaced a week later to enter rehab. Prior to checking in, he sent an email to friends apologizing for "worrying everyone" and vowed to commit to his treatment program.
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