US school gunman was interested in other mass murders; still no motive provided

NEW HAVEN, Conn. – The young man who killed 26 people at a Connecticut school last year showed interest in other mass killings, people close to the investigation told The Associated Press.

The 20-year-old gunman, Adam Lanza, killed his mother at their home before killing 20 children and six staff members on Dec. 14. He killed himself as police arrived.

Authorities found literature on other mass shootings at Lanza’s house, according to a law enforcement official briefed on the investigation. Another person familiar with the investigation said Lanza showed an interest in other mass murders. They spoke on condition of anonymity because the investigation is continuing.

The shootings revived the gun control debate in the U.S. and led to proposals for universal background checks on gun buyers and bans on assault weapons and high-capacity ammunition magazines. It also prompted reviews of school security and mental health care.

Police have declined to comment, and authorities have not provided a possible motive for the Connecticut shooting. A police report is expected around June.

The Hartford Courant and the Hearst Connecticut Media Group first reported Wednesday that Lanza had done research on other mass killings.

The Courant previously reported that investigators found news articles about Norwegian mass murderer Anders Behring Breivik at Lanza’s house. Breivik killed 77 people in twin attacks in 2011 in Norway’s worst peacetime massacre.

The latest discovery suggests Lanza didn’t act on impulse and might have used past mass killings as a guide.

“It certainly lends some evidence of prior planning and at least a fascination with these kind of incidents, if not using it as a way to sort of develop a plan,” said Jack McDevitt, associate dean in the School of Criminology and Criminal Justice at Northeastern University.

Other killers have been found with materials from earlier mass shootings or cited the crimes, said Jack Levin, a professor at Northeastern University who has written a number of books on mass murderers.

The massacre at Columbine High School in Colorado in 1999 has been cited by later killers in the United States and other countries, he said.

“The copycat phenomenon thrives on excessive publicity, and we have contributed a great deal by displaying excessively these horrific crimes in our popular culture,” Levin said. “The copycat phenomenon doesn’t cause the event to happen. It determines the timing and the method.”

Lanza, whose mother used to take him to shooting ranges, killed all of his victims with a semi-automatic rifle that was legally purchased by his mother. He used a handgun to kill himself.

Jeffrey Fagan, a Columbia law professor, said he doubted the materials planted the idea in Lanza’s head, but they could have given him guidance on tactics. He said it’s extremely difficult, if not impossible, to predict the effect of the materials.

“A would-be shooter could be just as likely to be turned off by exposure to the life histories or tactical details of other mass shootings, or those same details could push an unstable person from passive reading to active planning and ultimately action,” Fagan wrote in an email. “This is beyond finding a needle in a haystack, it’s more like finding a speck of dust.”