On July 27, 2008, people gathered in the sanctuary of the Tennessee Valley Unitarian Universalist Church in Knoxville to watch the children and youth of the congregation present the musical Annie Jr. Suddenly, a shot rang out. At first, many thought the noise was part of the musical, but they quickly realized there was a gunman in the sanctuary. Some people ran from the room, others threw themselves and their children under the pews. The gunman killed Greg McKendry when he moved in front of others to shield them from gunfire. The gunman wounded several other adults including Linda Kraeger, a visitor to the congregation, who later died of her wounds. People in the sanctuary tackled and subdued the gunman, who had concealed his shotgun in a guitar case as he entered the church. The police arrived and took into custody the shooter, David Adkisson. A witness said, "Everybody did exactly what they needed to do. There was very little panic, very little screaming or hysteria. It's a remarkable congregation of people. I've never seen such a loving response to such an overwhelming tragedy."
Adkisson, an Army veteran, had left a letter in his car expressing his frustration with being unemployed, and stating that he was motivated by hatred of liberals, democrats, African Americans, and homosexuals. He said in the letter that he had intended to continue shooting until the police came and killed him. The police affidavit reports that Adkisson later stated that, "he had targeted the church because of its liberal teachings and his belief that all liberals should be killed because they were ruining the country, and that he felt that the Democrats had tied his country's hands in the war on terror and they had ruined every institution in America with the aid of major media outlets." He further stated: "This isn't a church, it's a cult. They don't even believe in God. They worship the God of secularism. The UU church is the fountainhead, the veritable wellspring of anti-American organizations."
Press reports indicate that his former wife had at one time been a member of the church, but there is no evidence that Adkisson ever attended any events at the church. Nonetheless, he wrote, "They embrace every pervert that comes down the pike, but if they find out your [sic] a conservative, they absolutely hate you. I know. I experienced it."
In early 2009, Adkisson pled guilty to two counts of murder and six counts of attempted murder and was sentenced to life in prison.
The Tennessee Valley Church was rededicated a few weeks after the shooting and a relief fund for those affected was created in the Southeast District and at the Unitarian Universalist Association. Just before Adkisson's guilty plea in 2009, Tennessee Valley Unitarian Universalist Church named its fellowship hall for McKendry and its library for Kraeger.