Three Campbell schools were placed in "Code Blue" March 15 after a shooting in San Jose left an 18-year-old San Jose man with life-threatening injuries and a suspect at large.

's Sherman Oaks Elementary and Monroe Middle schools, as well as 's , were all placed under what's called Code Blue, essentially a lockdown of the school where no one goes outside, by both San Jose Police Department and by the school district.

"We received the call at around 12:05 p.m. that there was a shooting at the 800 block of South Bascom Avenue," said San Jose police spokesman Jose Garcia. "Apparently an unknown male walked up to the victim and shot him close range."

The suspect, described only as a male in his late teens or early 20s, was last seen running north on South Bascom Avenue, near the Taco Bell. No other description was released, because of conflicting statements from witnesses, Garcia said.

Sherman Oaks Elementary School and Del Mar High School were also placed under Code Blue by police because they're close by.

"It’s a standardized procedure," Garcia said. "There are no indications that there are ties between the suspect and any of those schools. No indicators that the suspect ran toward these schools. It was just a precautionary measure to safeguard the schools."

Monroe Middle School also was placed under Code Blue by Campbell Union School District as a precautionary measure after the school district received a call from the Sherman Oaks principal with an alert about the police activity nearby, said school district spokeswoman, Marla Olszewski.

"Monroe was letting out early yesterday due to minimum days," Olszewski said. "Before we let that happen, we wanted to be certain it would be OK to let them out at their minimum time. They were under lock down for 45 minutes. Thankfully, everyone was safe."

Del Mar High School was also placed on lockdown, a rarity within the Campbell Union High School District, said Terry Peluso, executive director of student services.

"This has been the only one experienced by any one of our high schools this year," Peluso said. "In the average year, you would have zero. It’s an unusual thing."

What happens during a "Lock Down"

Code Blue is part of a system in place at local schools that help police keep students and staff safe. It translates into keeping students and staff indoors and alert of any suspicious activity nearby.

"A Code Blue just says, in essence, don’t go outside," Peluso said. "It would be whatever classroom you are in; stay there until you hear differently."

There is one more level higher: a Code Red.

"It means stay in your classroom, lock your door, get to a corner of the room, barricade the door and stay as inconspicuous as possible, and police will actually come onto campus when it is safe to let students out, one room at a time," he said. "This would be used if there was a suspicion of someone armed on campus."

The two are usually issued by the local police department working a case but can also be issued by the school district as a precaution.

After this, notification is made to parents at each school

"Ordinarily, a message would come from the school," Peluso said. "Ordinarily, unless its prolonged, it would not come during the actual emergency."

The reason for this, he said, is three-fold:

• In the first place, during such an event, school officials have an immediate concern: the safety of students and staff. It is not a time where they would dedicate their time to get a message out to every parent.

• A second reason is that police don’t want parents at the school. First of all, it makes a traffic jam, and there's nothing parents can do. Secondly it creates a whole new set of people that are not sheltered and have to protect instead of the students at the school.

• Under these circumstances, police do not want to encourage a lot of cellphone traffic. If you get a lot of cellphone traffic back and forth, it overloads the system, and then no cellphone communication can get through. So if police officers are using the cellphone network in that area as a secondary form of communication, they can’t, because it’s overloaded. And that impedes safety. You want to make sure that police under those circumstances can do their job.

Police have identified the victim but will not release his location for safety reasons. The case is under investigation.