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."
A phone message left by The Associated Press at Lammers' home wasn't returned Friday. No attorney is listed for him in online court records.
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.
According to the probable cause statement, Lammers also planned to "just start shooting people at random" at a Walmart store less than a mile away. He said he'd purchased two assault rifles and 400 rounds of ammunition, and if he ran out of bullets, he would "just break the glass where the ammunition is being stored and get some more and keep shooting until police arrived," investigators wrote.
Lammers stated he wanted to stab a Walmart employee to death and followed an employee around a Walmart store before officers got involved in 2009, according to police.
When asked about recent shootings in the news, Lammers told police "he had a lot in common with the people that have been involved in those shootings," the probable cause statement said.
Police said Lammers bought one firearm Monday and another Tuesday. He then went to the Missouri town of Aldrich to practice shooting because he "had never shot a gun before and wanted to make sure he knew how they shot and how they functioned," the probable cause statement said.
More Nation & World Headlines
Russia launches airstrikes in Syria, says ISIS is target 8:37 a.m. Drivers on drugs: Study links roadway accidents to legalization of marijuana S. Sudan president, rebel leader trade blame for fighting GOP: Planned Parenthood spends federal money on politics Obama says fight against Islamic State group will take time Congress: U.S. fails to stop most people trying to join ISIS Yemen officials: Death toll from strikes on wedding at 131 CIA pulled officers from Beijing after breach of federal personnel records
Our new comment system is not supported in IE 7. Please upgrade your browser here.