NEW YORK (CNN) -- A man accused of entering New York's LaGuardia Airport with a bag containing wires and batteries has been indicted on terror-related charges.
Scott McGann, 32, faces an August 18 arraignment after he undergoes a court-ordered psychiatric evaluation.
Scott McGann, 32, was indicted Wednesday on charges of placing a false bomb or hazardous substance in the first degree; placing a false bomb or hazardous substance in a transportation facility; and making terrorist threats, according to Queens District Attorney Richard Brown.
If convicted, McGann faces up to seven years in prison, Brown's office said Friday.
McGann initially appeared in court Saturday, but his arraignment was postponed until August 18 pending a court-ordered psychiatric evaluation, Brown's office said.
McGann is being held at the Bellevue Hospital prison ward, according to the New York City Department of Correction.
Authorities said McGann walked into LaGuardia's central terminal on Saturday morning with what was determined to be a fake bomb. The terminal was shut down, then evacuated, but it reopened after several hours.
"The defendant is clearly a very troubled young man," Brown said. "As a result, the court has directed that he be examined to determine whether he has the capacity to understand the proceedings against him and assist in his defense."
McGann allegedly arrived at a checkpoint in the terminal at about 4:50 a.m. ET Saturday, carrying a backpack and refusing to answer security questions.
Authorities said the officer at the checkpoint was informed that a suspicious package was attached to the bottom of McGann's backpack and that McGann allegedly grabbed what appeared to be a trigger device with a red button connected to the backpack.
McGann allegedly pressed the button several times before an officer with the Port Authority of New York and New Jersey grabbed the trigger and the package away from him.
The package turned out to be a device consisting of batteries, cylinders and electronic components that could have been used to make a bomb, Brown said, but the bomb squad found that it didn't not contain any explosives.
McGann had a ticket on a United Airlines flight to Chicago, Illinois, and a seat on two other connecting flights with his final destination, Oakland, California, according to a law enforcement official close to the investigation.
McGann has three earlier arrests in the New York area, the source said. The most recent involved charges in June of tampering with evidence and resisting arrest. He also was arrested twice in 2008, the source said.
Port Authority spokesman John Kelly said McGann was "just acting crazy."
The arresting officers described McGann as "extremely disheveled and dirty" and in a "near catatonic state" and "staring off into space," Kelly said. McGann had been homeless for at least a year.
Authorities evacuated the terminal after 5:20 a.m. but allowed passengers back in to all areas except Concourse C by midmorning, Kelly said. The concourse was reopened shortly before 11 a.m. Saturday, according to Federal Aviation Administration spokeswoman Holly Baker.
Authorities had stopped flights from taking off or landing at the airport, but flights resumed shortly after 9 a.m., Baker said.
The incident disrupted travel plans for many passengers and caused American Airlines to cancel 16 flights, said an airline representative. American Eagle, Continental Airlines and Southwest also reported delays.
CNN's Chuck Johnston, Aspen Steib, Ross Levitt, Laurie Segall, Kristen Hamill and Susan Candiotti contributed to this report.