Police on Thursday were investigating a bomb threat toward Albert Einstein High School in Kensington Credit: Credit Gillian Huebner

Updated at 10:50 a.m. Friday: Montgomery County police are investigating to determine the source of a bomb threat that was emailed Thursday to the principal of Albert Einstein High School in Kensington, Capt. Paul Starks, a police department spokesman, said Friday. 

The school was placed on lockdown Thursday afternoon after the threat was received, according to a Montgomery County Public Schools spokeswoman said. The lockdown was lifted shortly after 3 p.m. after police searched the school and found no explosives.

Students at Newport Mill Middle School, which is next to Einstein, sheltered in place because of the threat, spokeswoman Melissa Rivera said.

Earlier Thursday afternoon, police tweeted that the emailed threat warned of an explosive device outside the school building. Police responded to the school to investigate and search the grounds with dogs trained to detect explosives.

The school’s 2:30 p.m. dismissal was delayed, but the MCPS tweeted at about 3:08 p.m. that students would begin leaving momentarily. Dismissal at Newport Mill Middle was delayed to 4 p.m., and afterschool activities at both schools were canceled.

Parent Gillian Huebner, whose son is a freshman at Einstein, said he texted her at about 2 p.m. saying students were on lockdown and had been told “it wasn’t a drill.”

“It’s horrible to get that text from your kid,” said Huebner, who serves on a school climate and safety subcommittee for the Montgomery County Council of Parent-Teacher Associations. “But I think the school system has done a remarkable job with communication, so I think that has calmed everybody down.”

Last week, Walter Johnson High School and Winston Churchill High School were evacuated because of bomb threats. Police investigated and determined both schools were safe.

This story will be updated.