As much as people say the FBI grooms shooters (which they have, as the Draw Muhammad shooter illustrated), the media definitely has a giant fucking role in it.
Roger Ebert in 2003 did a review on a movie about Columbine (Elephant) and he straight up told a journalist that "The message is clear to other disturbed kids around the country: If I shoot up my school, I can be famous. The TV will talk about nothing else but me. Experts will try to figure out what I was thinking. The kids and teachers at school will see they shouldn't have messed with me. I'll go out in a blaze of glory."
That's also what the Columbine shooters, Tarrant, and the V-Tech guy who mailed a box of photos to a news station wanted. The basement tapes featured the shooters bragging about how they'd be Hollywood famous and talked about which Hollywood director should make a high-budget biopic of their life. Different things from being taken alive to livestreaming the event are done to fuel the media coverage as well.
Ironically the only time the media will localize coverage of a mass murder event is if they're trying to memory hole it.