A Somali-born teenager who thought he was detonating a car bomb at a packed Christmas tree-lighting ceremony in downtown Portland, Ore., was arrested by the authorities on Friday night. Federal agents said that they had spent nearly six months tracking him and setting up a sting operation.
The bomb, which was in a van parked off Pioneer Courthouse Square, was a fake — planted by F.B.I. agents as part of the elaborate sting — but “the threat was very real,” Arthur Balizan, the F.B.I.’s special agent in charge in Oregon, said in a statement released by the Department of Justice. An estimated 10,000 people were at the ceremony on Friday night, the Portland police said.
Mr. Balizan identified the suspect as Mohamed Osman Mohamud, 19, a naturalized United States citizen. He graduated from Westview High School in Beaverton, Ore., a Portland suburb, and had been taking classes at Oregon State in Corvallis until Oct. 6, the university said on Saturday.
Mr. Mohamud was charged with attempting to use a weapon of mass destruction. “Our investigation shows that Mohamud was absolutely committed to carrying out an attack on a very grand scale,” Mr. Balizan said.
“At the same time, I want to reassure the people of this community that, at every turn, we denied him the ability to actually carry out the attack,” he added.
True as that may be, another failed terrorism attempt shows how the pace of attacks has picked up.