Alexander Song was arrested on campus Sunday. Police learned of the threat Saturday night when a former student police aide reported it to them, said Capt. Marc Limansky, a campus police spokesman. Detectives worked through the night to trace the message to Song, of Fulton, Md., police said.
The threats were posted on Reddit.com, a social news service, and Omegle.com, which enables users to have one-on-one anonymous chats.
Song, who was not armed when he was arrested, faces a misdemeanor charge of disturbing school activities. He was taken to a hospital for a psychiatric evaluation.
A police spokesman said it's unclear if Song has an attorney.
Song was a member of a campus research program for select honors students who explore how science and technology relates with society, according to the university's website. The Gemstone Program lists Song as scheduled to graduate in 2014.
Song was one of the leaders of a student research team, Be Pure, that was studying ways to make methane gas safe for energy consumption, said James Wallace, a mechanical engineering professor and director of the Gemstone Program.
Steven Hutcheson, the team's advisor, said Song had once been one of the more vocal members of the team but had recently appeared quieter. Hutcheson and a couple students who knew Song said there was no indication that he was unhappy or capable of violence.
"I wish there had been something because I would have loved to have helped him," Hutcheson said.
Anjana Sekaran, another member of the Be Pure team, said she had known Song since last year, "and he is a very intelligent, good-natured individual. He would never hurt anyone."
After the arrest, some students complained on Twitter that the school's emergency alert system was not activated after police learned of the threat. University President Wallace Loh said in a statement Monday that officials decided that sending out a campus-wide alert before Song was in custody threatened to interfere with their investigation.
"The police are confident that any threat to our community was mitigated once the student was taken into custody," Loh said.
