A 14-year-old boy accused of making threatening references to the 1999 Columbine High School shooting rampage is undergoing a mental health evaluation, a source said Friday.

Meanwhile, Henderson police said they were continuing to investigate the case. They would not say whether their investigation had turned up any other suspects.

"The investigation's still open, so we're talking to acquaintances of his," officer Todd Rasmussen said.

Authorities have been tight-lipped about the case because of laws restricting the release of information about children, but several sources in Clark County's juvenile justice system said they have learned the boy was sent to Montevista Hospital after his arrest.

Ingrid Whipple, chief executive officer of the psychiatric hospital, would neither confirm nor deny the information.

Susan Roske, chief of the juvenile division for the county public defender's office, was among those who have been told the boy was taken to Montevista.

Roske said her office has not been appointed to represent him, and she does not know his name.

"As far as I know, he has not been detained or appeared in court," Roske said.

Police said the boy was arrested on a charge of making threats or conveying false information concerning acts of terrorism.

The same felony charge recently was used to prosecute a man who made threats with an inert grenade on a packed shuttle bus headed to Primm.

At the time, District Attorney David Roger said he knew of no other instances in which his office had used the state's terrorism statute for a criminal prosecution.

Deputy District Attorney Karen James said the Henderson case has not been submitted to the juvenile division of the district attorney's office, "and we're the only ones who can file charges on juveniles."

"We have not received any paperwork with that type of charge on it in the past week," she said.

James said she does not know the boy's name or any other information about his case.

"To my knowledge, he's not detained, because the paperwork has not been submitted to the district attorney's office," the prosecutor said.

James said a juvenile suspect who is detained typically appears before a judge the next day for a detention hearing.

Juvenile suspects who are not detained, but have had charges filed against them, typically appear before a judge for a plea hearing in about three to four weeks, she said.

The suspect in the Henderson case is accused of sending threatening messages over the Internet.

Police said the messages did not identify a specific school, but the boy made several references to the shootings at Columbine High School in Colorado.

Rasmussen described the suspect as a "disturbed child" who had surveillance footage of the Colorado shooting on his home computer.

Similar footage is easily found on the Internet. The suspect also titled his MySpace.com Web page "R.I.P. Eric Harris and Dylan Klebold."

MySpace.com is a social networking Web site that gives users access to blogs, profiles, photos, videos and an internal e-mail system.

Harris and Klebold were the two teenagers who went on a shooting spree at Columbine High School in Littleton, Colo., near Denver.

They killed 12 fellow students and a teacher and wounded several others before committing suicide on April, 20, 1999.

Police learned about the threats in the Henderson case when they were called by a relative of a teenager who received a message from the suspect.

Rasmussen said the suspect sent a message from his MySpace.com account that stated, "Would you be down for some Columbine-like (expletive)?"

Police later searched the suspect's home and found no weapons.

"From what I read in the paper, it doesn't sound like a crime was committed," Roske said. "I'm very concerned if they detain this boy who may have mental problems, and I hope that his parents get counsel for him."

Roske said most children are released after police arrest them.

She said either authorities or the boy's parents could have placed him at Montevista Hospital.

Rasmussen said detectives learned that in previous years the boy had been suspended from school for such incidents as fighting, threatening other students and using slurs.

"In the recent past, he has been to several different schools," Rasmussen said.

Authorities have refused to identify the schools the boy has attended or the school he was expected to attend when the academic year begins next week.