SOUTH BRUNSWICK, NJ - Two visitors to the Indian Filelds Elementary School caused some tense moments Monday morning for not checking in at the main office, police said.

According to police a man and a woman entered the school at 9:45 a.m. after being buzzed into the building.

Staff at the school directed them to check in at the office, and when they did not, staff members contacted South Brunswick Police to report that the two individuals breached security procedures at the school.

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Police were called after the staff was unable to locate the pair, police said.

A dozen South Brunswick officers responded to the school and secured the building, evacuating the approximately 500 students as a precaution.

Police said the evacuation followed normal procedures in place at the school that are practiced every month.

The South Brunswick School District provided buses for the students to sit in during the incident, police said.

District officials did not return a phone call and message left with staff seeking comment.

Police said that officers conducted two searches of the school.

Detectives interviewed witnesses and visitors who had come to the school at around the same time as the incident.

Police said they then checked other area schools to see if anyone matching the description had entered.

Police located the two individuals at a different elementary school.

The two individuals were visiting the schools to talk about a summer learning program and mistakenly went to the wrong school, police said.

The two individuals realized they were not supposed to be at Indian Fields School and left the school shortly after entering.

The students all returned to their classrooms by 10:45 a.m. without incident, police said.

Chief of Police Raymond Hayducka credited school staff and officers with quickly resolving the situation.

“I was at the scene, the principal, teachers and staff did a great job of working with the students and making the evacuation an orderly process," he said. "The security drills the schools practice paid off today.”

Indian Fields School will follow normal dismissal procedures, according to police.