US researcher: Young shooters tend to research role models

MILAN (AP) — The U.S. psychologist who wrote a book about school shootings that investigators found in the Munich gunman's room says researching other mass killers can be a warning sign since young gunmen often are looking for role models — but it's just one of many possible indicators.

Peter Langman, author of two books about school shootings, told The Associated Press by telephone from Allentown, Pennsylvania on Saturday, that juvenile killers "more frequently study other shooters."

Langman said there are often a lot of warning signs before a shooting attack, and that "it is never one thing; it is always a combination of multiple factors."

The concept of threat assessment is the same across borders but each nation has differences based on things like the availability of weapons or the quality of mental health care, he said.