KANSAS CITY, Mo. (AP) — A man accused of plotting to open fire inside a Missouri movie theater during a "Twilight" showing and attack a nearby Walmart was arrested in 2009 after following a clerk at the same store with a knife and rubber mask, according to an arrest report released Tuesday.

Blaec Lammers told investigators he went to the Walmart in Bolivar in October 2009 looking for an "easy victim" after watching the horror film "Halloween," saying that watching the main character killing people "got him to thinking," the arrest report said.

Lammers told authorities he watched the clerk for more than two hours. He said he was planning to follow the clerk into a storage room and kill him when he heard his name over the public address system and his father calling his name, according to the report.

No charges were filed in that case. Instead, Lammers, who was 17 at the time, was committed for 96 hours for a mental health examination, Polk County prosecutor Ken Ashlock said Tuesday. Ashlock, who was not the county's prosecutor in 2009, said he didn't know what happened after the commitment.

Lammers, now 20, made his first court appearance Tuesday in the movie theater case and was ordered to undergo a mental health exam. Lammers, who is being held on a $500,000 bond, is charged with first-degree assault, making a terroristic threat and armed criminal action.

His public defender, DeWayne Franklin Perry, declined comment Tuesday.

His mother, who contacted police last week out of concern her son was planning a shooting, said Tuesday that he has shown signs of Asperger's syndrome, borderline personality disorder and other conditions. She said her son has had inpatient treatment in the past.

"He didn't ask to be born different. He grew up his whole life in (his sister) Kristyn's shadow. He wanted to be successful and be somebody," Tricia Lammers said during a news conference at the National Alliance for Mental Illness in Springfield, KLOR-TV reported.

"Just two weeks ago he asked me — both my kids still call me mommy — he said, 'Mommy, do you think I'm a failure?' I said, 'No Blaec, I don't.'"

Her son was arrested last week after she told police she was concerned he "may have intentions of shooting people" during the opening weekend of the final film in the popular vampire movie series.

According to a police probable cause statement, she said she believed her son had amassed weapons similar to those used by the gunman who attacked a theater in Aurora, Colo., during the latest Batman movie in July. That attack killed 12 people. Continued...