A Laurel high school student was admitted to a hospital for a psychiatric evaluation after police said he threatened to shoot and kill his classmates.
Peter Piringer, spokesman for the city of Laurel, said a police investigation found "charts, diagrams and lists" with plans to commit violence.
"He alleged that he was going to do harm, and possibly shoot and kill, among other things," Piringer said.
The announcement of the Laurel investigation comes days after the second-deadliest school shooting in U.S. history left 27 people dead in Newtown, Conn., and put school and law enforcement officials on heightened alert.
According to police, students at Laurel Senior High School told their teacher that a classmate had indicated that he was going to harm, shoot and kill other people.
Piringer said he didn't know if the student made the alleged threats verbally or in writing, or what caused the classmates to become suspicious about his behavior.
The teacher agreed with the students' concerns and relayed the information to school security, who passed it on to police.
The student's parents told Laurel police that their son had access to weapons, and investigators believed the threats were credible, Piringer said. The weapons were not on school grounds, he said.
The student, who is not identified, did not attend school on Monday. He was located off campus and taken to a hospital for an emergency committal for psychiatric evaluation, Piringer said.
"The Laurel police chief believes this is a prime example of 'See Something, Say Something,' " Piringer said, referring to the public awareness campaign to report suspicious activity to authorities. "This resulted in the prevention of a potential very dangerous situation involving high school students and others."
Piringer said he believes the behavior that led to the investigation occurred before Friday's mass murder at Sandy Hook Elementary School.
School systems and police throughout the Washington area say they are increasing their presence around schools this week to create ease in the community.