LAS VEGAS >> A 9-year-old boy arrived at school Monday with a grisly story: His mother and sister were dead at their home four blocks away.

Minutes later, police found the bodies of a woman and a girl — along with a blood-covered man and an unharmed 4-year-old child — in the modest home in a West Las Vegas neighborhood.

The man, who had unspecified injuries, has not been identified as a suspect or charged. Police say the five people belong to a single family.

"I walked past there every day," neighbor Dick Webb, 82, said about the house.

He said he had walked past the house less than 90 minutes before the boy arrived at school but hadn’t seen anything amiss.

Police said the boy was uninjured when he arrived at Mabel Hoggard Elementary School, where his sister also was enrolled.

Principal Celese Rayford declined comment.

Clark County School District spokeswoman Amanda Fulkerson said the campus, with about 450 students in grades kindergarten through 5, was "struggling to sort out emotions and details of a tragedy that claimed the life of a student at home this weekend."

Fulkerson wouldn’t provide details of the slayings but said school administrators quickly notified police about the boy’s report.

Students were being reminded that school "is always a safe zone with caring adults that can help in uncertain situations," Fulkerson said.

Officer Jacinto Rivera told reporters that investigators were working carefully inside the single-story stucco home.

"We get one shot at a homicide scene. Our No. 1 priority is to find out what happened," he said. "Right now we don’t know what happened."