A Lexington, Mass. man pleaded not guilty today in district court to making threats that forced Lexington High School to close early Thursday, The Boston Globe reports.

Myles Fulton Penniman, 20, pleaded not guilty to a charge of making a bomb threat and a charge of disrupting a school. At the request of Middlesex District Attorney Marian T. Ryan's office, bail was set at $5,000 cash for Penninman, who was placed on house arrest with GPS monitoring, prosectors said.

On Thursday, Lexington Police arrested Penniman and a juvenile from Belmont, Mass. after school officials received information about a possible threat to students and staff. Both were charged with threatening a school and disrupting a school. After learning of the threat, the high school dismissed students at 1 p.m., closing the campus and canceling all after school activities.

Advertisement - Continue Reading Below

Penniman is a former Lexington High School student and currently attends Clark University, WHDH reports.

Prosecutors said Myles Penniman sent out texts promising "Columbine-style violence" at the school, and that he targeted developmentally delayed students.

According to WBZ, Penniman and the unidentified juvenile allegedly sent the threats in a group text message and also made references to Newtown, Conn. shooter Adam Lanza.

Two Lexington High sophomores included in a group text reported the threats to school officials.

According to the prosecutor, the texts read in part "We are gonna kill the teachers at 3? Lex High is in trouble. U heard O Lanza? Let's go for the LAB kids first."

LAB refers to a class for developmentally challenged students.

Classes resumed Friday, May 23, at Lexington High.