Hillsborough High School was closed following a lockdown on Friday, April 29, 2016.
This article has been updated to include information released by the school and police.
HILLSBOROUGH - Students at Hillsborough High School were sent home at noon Friday after the school was placed on a lockdown shortly after 10 a.m., according to the school district.
Principal Karen A. Bingert, in a letter released Friday afternoon, said two people entered the school as students arrived, but left "without obvious incident." After school officials were notified of the two being in the building, the school was placed on a modified lockdown and police were contacted. NBC New York stated that there were reports of "rowdy trespassers," but this could not be confirmed.
Hillsborough High School posted an update at 3 p.m. stating that certain events scheduled at the school, including a Battle of the Bands at 7 p.m., will continue, as will a boys tennis match, while "all other practices, clubs, and activities remain cancelled today."
Any events scheduled to take place at the school on Saturday will go ahead as planned, she said.
Bingert said several police agencies responded to the school.
"Working collaboratively with the police, who mustered the additional resources of New Jersey Detect and Render Safe (which includes the regional K-9 task force), we secured dogs to check the parking lots and building to make sure that nothing dangerous had been left behind," Bingert said. "In order to do this, we needed to restrict movement inside and outside the building, which resulted in the decision for an early dismissal today. This dismissal occurred at noon, which is our normal half-day dismissal time."
Bingert said police dogs checked the parking lots prior to students being dismissed, and the building after students left.
"The Hillsborough Township Police Department is continuing its investigation to determine the identity and purpose of the trespassers," Bingert wrote.
Hillsborough Police, in a statement released at 6 p.m., said the department is continuing to attempt to identify the two men. They were not current or former students and did not have any reason to be at the school, according to the police. They left before police arrived.
A report on mycentraljersey.com said a parent turned to a Hillsborough Community Facebook page to report "that her daughter texted her saying she saw two guys in their 20s walking around the commons."