WASHINGTON (AP) — In his long-winded video diatribe, Seung-Hui Cho referred to the Columbine school killers as martyrs, and his crime inevitably has been compared with theirs.

Now, experts fear, other vulnerable, angry boys may try to copy or surpass Cho’s massacre. As of Friday, the FBI counted 35 to 40 mostly school-based threats, with everything from bombs to guns to mere words, some leading to arrests.

“This is serious business. This is not a time for jokes and it needs to stop,” said FBI special agent Richard Kolko, who said all must be investigated. “These threats are abhorrent and those that make them are subject to prosecution and serious prison time.”

The FBI asked that people be alert to potential attacks and to contact law enforcement officers.

There have been times in recent history when shooting sprees seem to occur in clusters. It’s a copycat or contagion effect, experts said.

“After there’s one, we see a couple more,” said Marisa Randazzo, the former chief psychology researcher for the U.S. Secret Service and co-author of a major federal study examining the common threads of 37 school shootings.

For example, when a gunman shot a student and killed himself in September 2006 at a Bailey, Colo., high school, it was the first report of a school shooting in three years. After the Colorado slaying, there was the mass shooting a month later at an Amish school in Nickel Mines, Pa.; a student killing another student at a high school in Tacoma, Wash., in January; and now the Virginia Tech massacre.

Experts say the first such shooting doesn’t create a killer. But it can push an already troubled person over the edge.

“A shooting like that may help to shape ideas and plans that a suicidal child already has,” Randazzo said.

Loren Coleman, a psychiatric social worker in Maine who wrote “The Copycat Effect,” said “celebrity school shootings actually increase the suicide rate and increase the violence rate for a short period of time.”

Most of the copycats considering suicide or homicide feel “desperation, despair and often hopelessness,” said University of South Florida professor Randy Borum, another co-author of the federal study of school shootings. “Now, look at the images and presentation of Cho in the media ... It is difficult to think of how one might create a more powerful image. If that is what others who may be feeling desperate and out of control are identifying with, I am concerned about that.”

And the media plays a big role too, experts said.

“We keep fueling the contagion everytime we show footage of Columbine-style kids jumping out the window,” said Northeastern University criminal justice professor James Alan Fox. He and others also are troubled by references to the Virginia Tech massacre as setting a record for the deadliest shooting in modern U.S. history.

Since then, some of the threats, including one in Yuba City, Calif., have mentioned attempts to shatter the Virginia Tech mark.

“These people are psychologically competing with each other to increase the body count,” Coleman said.

The FBI’s Kolko said “wall-to-wall media coverage could certainly be a factor in the copycat threats.”

Bob Steele, journalism values scholar at the Poynter Institute in St. Petersburg, Fla., defended the coverage, saying, “Statistics give context. Statistics help people understand the scope of the event or an issue.

“While it’s possible the coverage of this mass murder and his slaughter of innocent people could prompt copycats, the coverage could also prompt other individuals to back away from some sort of violence. The coverage could also prompt all of us to reach out and help those who need a firm hand in troubled times,” Steele said.

Randazzo and Kolko said one positive of the heavy coverage is that people become more aware so that potential attacks are stopped. Randazzo mentioned a 2001 Columbine-inspired plan in New Bedford, Mass., that was interrupted by another student’s tip. The would-be attackers had weapons, ammunition, bomb recipes, duct tape, wire and photographs of Adolf Hitler.

———

AP researcher Rhonda Shafner contributed to this report.