In response to a possible threat against one of its teachers, Hillhouse High School became the third New Haven school in the past 30 days to enter a campus lockdown.

At 10:04 a.m., the New Haven Police Department received the the threat through a call made at a local phone booth. An article from the New Haven Independent said the caller told dispatchers he was on his way to the high school to shoot a specific teacher. According to the Independent, NHPD Assistant Chief Achilles Generoso said that the lockdown had been partially lifted at 11:50 a.m. in order to let parents — entering the high school two-by-two — retrieve their children.

“Out of an abundance of caution, the school was placed on lockdown and the superintendent, principal and school officials are working with police to address the situation,” Abbe Smith, the Director of Communications for the New Haven Public Schools said in a press release.

Smith also described the school’s standard security measures, which include metal detectors and “school resource” officers. Both were active this morning, as they are to be every day.

“The safety and wellbeing of our students and staff [is] always our top priority,” Smith added in the release.

Hillhouse High School is located at 580 Sherman Parkway.