(CBS News) As fans of the "Twilight" series flocked to theaters this weekend to see the conclusion of a love story, police say Blaec Lammers bought his ticket intent on unleashing a shooting spree on Sunday, first at a theater in Bolivar, Mo., then at a nearby Walmart.
The 20-year-old Lammers recently bought two assault rifles and 400 rounds of ammunition. It was his own mother who tipped off the authorities on Thursday.
Darin Chappell, a Bolivar City administrator, said, "I think it takes a tremendous amount of courage for a family member to recognize the kind of threat that this posed, and to put the safety of others ahead of the concern for her loved one."
The advance planning was seemingly similar to that carried out by gunman James Holmes, who killed 12 people and injured 58 others in Aurora, Colo., during a midnight showing of "The Dark Knight Rises" in July.
In court papers, Lammers was described as "off of his medication" and seemed to identify with Holmes, describing himself as "quiet, kind of a loner" and "had homicidal thoughts."
Fortunately for "Twilight" fans, those thoughts never turned to actions.
To watch Jeff Glor's report, watch the video in the player above.
CBS News senior correspondent John Miller, a former FBI assistant director, speaking about copycat crimes, said Lammers seems to have been inspired by Holmes.
"Talking to the (criminal) profilers, what they say it's not that normal people see it and say, 'I think I will do that.' They say other disturbed people who are already planning to do something like this will see another successful model that happens -- successful for the perpetrator -- and they will get excited and they will want to adapt that into their plans," Miller said. "I think that's exactly what we are seeing here, this case with Lammers...and Holmes.
For John Miller's full analysis, watch the video in the player below.
After Holmes' attack, Miller said the movie industry grew concerned about copycat killers.
"They looked at the Aurora thing and said, 'Is this a one off?' Since then, there were a couple others that were interdicted," Miller said. "Nothing that had gone along this far. ... What's concerning them is, there's a model of this. You get fired from your job. You come back to the workplace, you open fire and people say, 'Well, this is the actor acting out against the people who wronged him.' You're isolated at school, you're ostracized, and you see a Columbine case. But when they're seeing an active shooter focused on high-profile events where the intended victims have nothing to do with the alleged grievances, they get concerned that they are picking events simply because they are high-profile and because of what FBI profiler Mary Ellen O'Toole explained...as hunting behavior. They can find a confined space with limited access where they can have maximum lethality where the victims are basically trapped there."