MISSION, Texas (ValleyCentral) — A 19-year-old man was apprehended after police say they found a loaded M4 rifle in a car at Veterans Memorial High School.

Chief Cesar Torres said that police received a call from a citizen at 10:27 a.m. that identified an individual driving into the school with a rifle and mask. An investigation revealed that he was coming to pick up his brother from the campus.

The individual, a 19-year-old man, was taken into custody. Torres added that the man exited the car and walked onto the property. Police did not locate a mask, but found a loaded M4 rifle that he left in the car, Torres said.

The man is now being interviewed by investigators.

“This kind of threat we do not take lightly,” Torres said.

Along with Mission police, the Texas Department of Public Safety and Constable Precinct 3 responded to the campus.

In a letter sent to parents, Mission CISD stated Veterans Memorial High School was placed on lockdown in response to a report of a weapon being brought on campus by a visitor. The individual was apprehended, the district stated.

A letter sent to parents on Tuesday from Mission CISD stated there were a series of “verbal arguments” among students that escalated into a verbal altercation. As a result, the students were dismissed in smaller groups, and there was added security precautions for the remainder of the week.

This is a developing story.