LAS VEGAS -- Tuesday was the first day back at school for Palo Verde students, four days after Christopher Privett was shot and killed, minutes after classes were dismissed Friday afternoon.

A memorial to Privett has grown since the weekend, and on Tuesday, Palo Verde students wore white T-shirts in honor of him.

Security was tighter than usual at Palo Verde and other high school around the Valley Tuesday.

Grief counselors were brought in to talk with Privett's classmates and students, who tried to make sense of it all.

Metro Sheriff Doug Gillespie was among officials at Palo Verde High School who met with reporters.

He said charges could be filed against the four other people who were in the car with the gunman when Privett was shot.

"The investigation is ongoing, and if we determine that we have probable cause for an arrest, these particular individuals, we will make it at that time," Gillespie said.

School Superintendent Walt Rulffes said the school district is doing everything it can to make sure schools in the Valley are safe.

The shooting did not take place on campus grounds.

Police said they still don't have a motive, and right now, they are treating the incident as a random act of violence.

The juvenile accused in the shooting made his first court appearance on Tuesday.

He will be tried as an adult.

He was holding his father's hand while the judge spoke.