Pierce Middle School in Milton went into lockdown Friday as police recovered three bullets from three separate bathrooms, according to authorities.
Milton School Superintendent James F. Jette, in an e-mail to families sent Friday afternoon, said “live ammunition” in the form of a 9mm bullet was found at 10:10 a.m. in the sink of a second-floor bathroom, prompting the lockdown and a 911 call to police.
“Unfortunately, upon further investigation two additional bullets were found in two separate bathrooms which heightened the concern and prolonged the lockdown,” Jette said, adding that Milton police called Boston and Quincy police for assistance with trained ballistics dogs to ensure no weapon was in the building. No gun was found.
“After a thorough sweep of the Pierce Middle School, the lockdown was transitioned to a stay-in-place and we were able to deliver lunch to students and they were able to move about in their classrooms,” Jette said.
He thanked police for their response and praised “students and staff for how they conducted themselves during this highly stressful situation,” with everyone following proper protocols for such events.
Jette, who’d earlier sent other e-mail messages to families keeping them updated on the fluid situation, thanked parents for their patience as well.
“I know how much anxiety and fear these situations evoke along with the need to know exact details,” Jette said. “As I stated in earlier communication with you, our number one priority is the safety and security of our students and staff in the building.”
Milton police said via Facebook at 11:18 a.m. that an “unspent 9mm round was discovered in a bathroom by a teacher just after 10:00 this morning. At this time there is no active threat.”
It wasn’t immediately clear how the bullets had ended up in the school.
Separately Friday, Salem police said in a statement that they were responding to a threat against a school.
The statement said police had received a 911 call that included “various false reports of shots fired, profanity, and hang-ups. The same caller also alleged that he was going to stage a shooting attack on Collins Middle School.”
The department said it had already been operating at a “heightened security stance” at local schools owing to recent mass shootings around the country.
Though officials didn’t deem Friday’s Salem threat credible, the statement continued, “out of an abundance of caution ... we have assigned a police presence throughout the day to Collins and further increased our overall coverage of all schools in Salem.”
Salem police said they were investigating the source of the calls.
“The Salem Police Department views threats to the safety of our children as our highest priority,” the statement said.
Jonathan Wiggs of the Globe staff contributed.