MISSION VIEJO – Kids playing at a school playground discovered 15 nails at the bottom of a slide Wednesday morning, apparently placed there with the express intent to hurt someone, authorities said.

The 1-inch nails were found in a playground on the grounds of Glen Yermo Elementary, a school located at 26400 Trabuco Road, said Jim Amormino, spokesman for the Orange County Sheriff’s Department.

“This is a serious crime,” Amormino said. “We’re going to find out who did this.”

The roofing nails were found by children at the bottom of a slide, but none of them were injured, Amormino said. By 1:30 p.m., forensic investigators arrived at the school to investigate the area where the nails were found.

Investigators with the sheriff’s department are investigating the incident, and they believe the nails were placed there intentionally.

The nails were found just after 10 a.m. with the points facing upward, hidden inside the sand of the playground, giving officials the indication they were not accidentally dropped in the area.

Investigators are searching the playground for other objects, he said. Authorities have also used metal detectors to comb the area.

Lt. Mike Gavin, chief of police services for Mission Viejo, said authorities were looking into all possible leads in the case, including a nearby condo complex where workers were reroofing the buildings.

“There are boxes with similar-type nails (at the condominium complex), but we’re looking into every possibility,” Gavin said.

Meanwhile, parents said they were shaken by the discovery, but hopeful it was an isolated case.

“(The incident) is a little scary,” said Shannon Medina, who has two children who attend the school. She said she was concerned, but not so much that she won’t send her kids back to school on Thursday.

Emory Bestenleher, who has a child at the school, said he hoped the incident was nothing more than a bad prank by teenagers.

“Thankfully, no one was hurt,” Bestenleher said, though he admitted he was slightly concerned. “I’m glad the local law enforcement is on it.”

The incident is reminiscent of several incidents in 2002, when razor blades and shards of glass were found in eight parks in the South County area between April and June. A Mission Viejo woman, Lori Fischer, was convicted of those incidents and sentenced to probation.

In 2004, Fischer was arrested again after she called authorities, stating she was afraid she might hurt someone again. Deputies found nails and a knife inside her car. She was sent to state prison to complete her sentence.

Glen Yermo Elementary has about 600 students enrolled at the campus in Kindergarten through sixth grade. Access to the campus is blocked off to vehicles after hours, but it is still accessible to pedestrians.

On Wednesday afternoon, investigators cordoned off a large portion of the school’s playground, including a large playground that has five slides. Tetherball, handball, and swing areas were also marked off by yellow tape. A janitor could be seen combing through a sandbox looking for objects.

Contact the writer: shernandez@ocregister.com or 949-454-7361