'No idea what happened': US man vanishes in Syria Obada Mzaik, seen in this undated family photo provided by Dr. Firas Nashef, has been missing nearly three weeks after traveling to Syria on Jan. 3, according to relatives. A 21-year-old Syrian-American has been missing for three weeks after returning to Syria from suburban Detroit, according to a family member in Michigan. Obada Mzaik flew to Damascus from Detroit Metropolitan Airport on Jan. 3, but wasn't seen leaving an immigration checkpoint, Dr. Firas Nashef, his uncle in Farmington Hills, said. Mzaik, who was born in Columbus, Ohio, was planning to study civil engineering at Al-Yarmouk University. The brother, Obaie Mzaik, 19, who was on the same flight, was not detained in Damascus, Nashef said. "It's horrendous because knowing what we know about the prison system over there, anything goes," Nashef told the Detroit News Monday. The prison system and justice system over there is not very impressive. He added that Mzaik had been detained in Syria for 37 days last year, but had not been charged officially. The State Department said it was aware of the matter and was working with authorities in Syria. 'Deep concern' The Detroit News noted that a Facebook page, entitled "Freedom to our friend Obada Mzaik," has been set up. It had 1,220 likes as of early Tuesday morning. A link on that page led to a petition on the www.change.org website, which urges the State Department to help free Mzaik. "As Syrians looking for freedom, we are outraged by the obscure circumstances surrounding Obada's arrest, and we express our deep concern over his safety in the Syrian regime's custody," the petition says. One message, which msnbc.com was immediately unable to verify, says "because he is my son ... I want him free and now.