A 911 call to police Thursday alerted them to the escape, the Las Vegas Sun reported.
Multiple police and animal control units responded to the scene to recapture the chimps -- one male and one female, each of which weighed about 170 pounds, said police spokesman Officer Marcus Martin
Neighbors said the chimps appeared agitated and were acting as though there were going to attack. The female jumped on top of a car and tried to open the door, Martin said. The male climbed on top of a police squad car and banged on the top of it.
"When you see the size of these animals, we think reasonable people would understand [to stay away]," Martin said.
The female chimp was tranquilized about 11:45 p.m. while the male was shot and killed when it headed toward residents, including children, who had come outside to watch the chase.
The surviving chimp was returned to its owners, David and Sheri Potochan, who had been approved by the county to keep exotic animals, Clark County spokesman Dan Kulin said.