Four public school campuses were locked down Monday while police searched for a teenager who was spotted at a high school with a gun, authorities said.
No shots were fired, and police said they had no indication the teen - a former student who had been banned from Mojave High School - had threatened anyone.
Police gave up their search of a residential area in suburban North Las Vegas after more than three hours.
"We know who he is," North Las Vegas police spokesman Tim Bedwell said. "He will be found eventually."
Bedwell would not disclose the teen's name or age, but said he believed the youth had been expelled or transferred from the high school for academic or disciplinary reasons.
The teen ran from the Mojave High campus when school police recognized him and confronted him about 7 a.m., authorities said. School police reported finding a .25-caliber handgun behind a nearby church.
About 2,300 students at the high school and 2,900 youngsters at two nearby elementary schools and a middle school were locked down during the police search of a square-mile residential area. The security measure meant students were kept in rooms while instruction continued, said David Sheehan, a school district spokesman.
The Clark County School District, with about 300,000 students and 325 schools, is the fifth-largest district in the nation.
Bedwell said the teen could face charges including trespassing, possession of a handgun by a minor and possession of a weapon on school property, a felony.
School districts across the country have been especially sensitive to threats after deadly shootings last week at schools in Wisconsin and Colorado, and then another on Monday in Pennsylvania's Amish country.
On Friday, a school principal was gunned down in Cazenovia, Wis., and a 15-year-old student was charged with murder. Just two days earlier, an adult gunman held six girls hostage in a school at Bailey, Colo., before killing a 16-year-old girl and then himself.