OXNARD, Calif. -

The quick work of an on-campus officer kept a young man armed with a fake gun off a high school campus.

"He did not have the ID so I didn't let him in," said Campus Supervisor Sharon Mauricio.

Mauricio was monitoring the gate at Pacifica High School in Oxnard when police say  20-year-old David Hernandez approached her on Tuesday afternoon.

"He asked to see the school psychologist... I told him he would not be able to go in without the ID I noticed he had something under his poncho and I asked to see it," said Mauricio.

On-campus Oxnard police Officer Pedro Rodriguez noticed the confrontation and stepped in.  "I told him that I needed to talk to him.  He started to reach into his waistband and at the point I was in close proximity and I didn't feel safe so I got control hold of his arm," said Rodriguez.

Officers bringing truant students to the campus noticed the struggle Rodriguez was in.  They stepped in to help Rodriguez and that's when they noticed what Hernandez was hiding: a replica handgun concealed in his waistband.

"If he would of gained access, well I don't know what his intentions were, but it could have been a bad situation for all of us," said Rodriguez.

One thing unique to the high schools in the Oxnard School District is they are all closed campuses, which means no one gets in or out without going through a campus supervisor.

"We screen every visitor that comes onto campus.  They must provide identification and sign our forms saying they are going to be visitors here on campus," said Rodriguez.

Not only are the campuses gated but they are also monitored by Oxnard police officers.  Each high school in the Oxnard School district is assigned an officer.  That officer's primary responsibility is to serve that school.  All school resource officers go through special training, including active shooter scenario training.