An elementary school teacher charged with shooting his principals had been warned for yelling at students and told he wouldn't have a job next term, school officials said Thursday. They also investigated a November complaint that he was unstable but didn't consider him an "imminent threat."

Knox County Schools Superintendent James McIntyre Jr. said Thursday that Inskip Elementary School teacher Mark Stephen Foster, 48, had been told on Wednesday, before the shooting, that his contract was not being renewed.

Police said Principal Elisa Luna and Assistant Principal Amy Brace were shot multiple times each in the school by Foster about an hour after classes were dismissed early for snow.

Foster, of Clinton, was charged with two counts of attempted first-degree murder and unlawful possession of a gun on school property after the shooting in north Knoxville. He is being held on a $1 million bond.

Luna was in critical condition on Thursday morning. Officials could not release an updated condition on Brace, but she was reported in stable condition Wednesday night.

McIntyre said the contract decision was made by Luna and he couldn't say what prompted her decision. Personnel records showed Luna had admonished Foster last week after getting a complaint that he yelled at students.

Foster told Luna and Brace that he had "been under pressure repeatedly" in response to thenidentified woman complained in March 2009 that Foster had threatened her for giving him a bad haircut. No action was taken against him in court in either case.

In seeking an order of protection against his brother, Anthony Foster claimed Mark Foster had threatened him after learning he was not named executor of the will of their mother.

"I am very afraid what he might do to me or my family. He suffers from mental illness and has been treated for it for several years," Anthony Foster wrote. "I fear for my and my family's life."

By state law, Tennessee Bureau of Investigation background checks are conducted on all prospective teachers. Foster's background check, which included a fingerprint search, drug test and review of Department of Children's Services records, was clean, McIntyre said.

Foster was hired by Knox County Schools in August 2008, and was at least one more school year away from being eligible for tenure.

Tennessee Department of Education spokeswoman Amanda Anderson said background checks will turn up criminal convictions but won't generate information about orders of protection that have been dismissed or basic complaints to police.

"It's a really thin line," she said. "Sometimes when you have issues like this there are warning signs that never show up in the background checks."