Updated

A University of Maryland honor student who warned on websites he was going to "kill enough people to make it to national news" was arrested after several people reported the threat to police, perhaps thwarting a campus rampage apparently planned for Monday, authorities said.

While the threat was dismissed by some online as harmless, a former student who used to work with campus police took it seriously and first called authorities Saturday night. By Sunday, authorities had set up surveillance on Alexander Song and arrested him on campus.

Song, a 19-year-old sophomore, was shaking and crying when he was taken into custody, campus police chief David Mitchell said.

"The best security we have is us looking after each other," Mitchell said. "And that's exactly what happened. Three people saw online postings and called us."

Song was not armed at the time of his arrest, and police did not find any weapons in his dorm room or his parent's home in Fulton, Md. Students and professors who knew him said there was no indication he was capable of violence.

Song was taken to a psychiatric hospital for an evaluation and suspended from the school. He faces a misdemeanor charge of disturbing school activities. Police did not know if he had an attorney and a working phone number for his parents number could not immediately be found.

The initial threat was posted on Reddit.com, a user-generated news website. Police said two more threatening posts were reported anonymously by people who were chatting with Song on Omegle.com, a website that enables one-on-one anonymous chats. In one of the chats, a person said he was going to call the police unless Song admitted that he was joking around, the police chief said.

Song responded by saying words to the effect of, "LOL. Go ahead. You don't even know what campus I'm talking about," the chief said.

Song also warned people to "stay away from the mall" on Monday, apparently alluding to a central lawn on campus.

Detectives traced the messages to a computer used by Song and arrested him on campus after setting up surveillance to track his movements.

Song was questioned about a week ago after police responded to Song's dormitory after a report of a man screaming, authorities said.

"He told us he was feeling a little stressed out. There was nothing that would lead us to believe that he was a threat to himself or others," Mitchell said.

It's unclear exactly what was stressing Song out, police said.

Song was a member of a campus research program for select honor 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."

Maryland College Student Charged In Rampage Threat: MyFoxDC.com