A southwest Missouri man accused of plotting to shoot up a movie theater during the new "Twilight" film was charged today after his mother contacted police, telling them she worried her son had purchased weapons similar to those used during the fatal Colorado theater shooting, The Associated Press said.

Blaec Lammers, 20, of Bolivar, is charged with first-degree assault, making a terroristic threat and armed criminal action. He was jailed in Polk County on $500,000 bond.

"Thankfully we had a responsible family member or we might have had a different outcome," Bolivar Police Chief Steve Hamilton told The Associated Press. He said Lammers is under a doctor's care for mental illness, and court documents said he was "off of his medication."

His mother contacted authorities Thursday, saying she worried that with this weekend's opening of the final film in the popular Vampire movie series, her son "may have intentions of shooting people at the movie," police wrote in the probable cause statement.

She said she thought the weapons — two assault rifles and hundreds of bullets — resembled those used by a gunman who opened fire inside a theater in Aurora, Colo., during the latest Batman movie in July. That attack killed 12 people.

Lammers was questioned Thursday afternoon and told authorities he bought tickets to a Sunday "Twilight" screening in Bolivar and planned to shoot people inside the theater. The town of roughly 10,000 people is about 130 miles southeast of Kansas City.