Matthew David Cole, 18, was charged Thursday with making threats of mass violence and disturbing the operation of the school. He posted $100,000 bail and was released from jail Friday.
"A thorough investigation is continuing, however, at this time it has been determined that there is no longer a threat to the university community," officials wrote in an email to students and staff.
No attorney was listed for Cole, and he did not respond to a phone message left at his Elkridge home.
The investigation began Wednesday when a worried student saw the messages on Yik Yak, an app that lets people in the same area send one another anonymous messages, and showed them to her resident assistant, said Gay Pinder, a spokeswoman for the school.
The first message read: "I plan on shooting up this [expletive] school on October 4th." The second made the comparison with the Virginia Tech massacre. In 2011, a Virginia Tech student shot and killed 32 people and wounded 17 others in two attacks.
Because a home football game was scheduled Saturday, campus police got local and state police and the FBI involved to be ready to respond to an attack and to aid in the investigation, according to charges filed against Cole.
Yik Yak advertises its privacy features and does not require users to register with a name or email address. But it also says in its terms and conditions that it will hand over data it obtains — including GPS information and IP addresses — if lawfully asked to do so by police.
Investigators used that information and other technology to track down Cole, according to court documents. The exact methods police used were not described.
Once police identified Cole as a suspect, they matched the time and location from which the Yik Yak messages were posted to Cole's schedule, which showed he was supposed to have been in a jazz history class in a nearby building.
On Thursday, campus officers went to pull Cole out of class, according to charging documents. Police wrote that when they told Cole they wanted to talk to him about Yik Yak, he said: "Oh, after I did it I knew I could get in trouble."
Cole waived his rights and told police he had learned he wasn't performing well in the jazz class and was worried his parents would pull him out of school if his GPA dropped too much, according to the documents. It was at that point he made the postings, police wrote, but he didn't expect anyone would take them seriously and gave a written statement saying he didn't mean to harm anyone.
"I knew there would be some kind of consequence," Cole said, according to the police account. "This, or karma related."
Cole is not the only person in Maryland in recent months to get into trouble over posts on Yik Yak.
In April, officials at Frostburg State University launched an investigation after someone posted that they were going to come to the campus and "start shooting." Police identified the person and determined he or she did not have the means to carry out the threat.
Baltimore Sun reporter Carrie Wells contributed to this article.