EDITOR'S NOTE: This story has been updated throughout. 

A man was arrested Wednesday after police found a rifle in his vehicle outside of Veterans Memorial High School in Mission, according to police.

Police responded to the campus after a witness reported to police that he saw a male wearing a mask place a rifle in the trunk of his vehicle and driving into the school, according to a news release from the Mission Police Department.

Officers who were already on campus located and arrested the individual inside the school. A rifle was located in his car, no mask was found, police added.

It's a criminal offense to possess a firearm on school grounds in Texas, according to the release. The driver is expected to be arraigned on Thursday, May 18, police added.

Due to the incident, the campus was temporarily placed on lockdown.