KNOXVILLE, Tenn. — An unemployed man accused of opening fire with a shotgun and killing two people at a Unitarian church apparently targeted the congregation out of hatred for its liberal social policies, police said Monday.

Knoxville Police Chief Sterling Owen IV said a letter had been been recovered from the SUV of Jim D. Adkisson, 58, by investigators seeking clues about the motive behind the attack. Authorities said he was an apparent stranger to the Tennessee church where gunfire punctuated a children's performance based on the musical "Annie." Two people were killed and seven wounded Sunday.

"It appears that what brought him to this horrible event was his lack of being able to obtain a job, his frustration over that and his stated hatred of the liberal movement," Owen said at a news conference.

No children were hurt, but five people remained in serious or critical condition Monday. A burly usher who died is being hailed as a hero for shielding others from gunfire Sunday at the Tennessee Valley Unitarian Universalist Church. Witnesses said some of the men present tackled a man who pulled a shotgun from a guitar case before at least three blasts rang out.

Adkisson, who is charged with first-degree murder, remained jailed Monday under "close observation" on $1 million bail, authorities said.

The Unitarian-Universalist church promotes progressive social work, including advocacy of women and gay rights. The Knoxville congregation also has provided sanctuary for political refugees, fed the homeless and founded a chapter of the American Civil Liberties Union, according to its Web site.

Owen said the letter indicated Adkisson, who neighbors said had previously worked as a truck driver, did not expect to leave the church alive. He added the man also reported having no family or next-of-kin.

"He certainly intended to take a lot of casualties," Owen said. "He had 76 rounds with him."

Police said Adkisson carried a 12-guage semiautomatic shotgun into the church in a guitar case, but it appeared no specific person was targeted in the church. A search of his house also turned up a .38 caliber handgun, Owen added.

Investigators were reviewing several home video recordings of the children's performance for any evidence. Owen said police don't plan to release those videos and they did not make public a copy of Adkisson's letter.

Unitarians have roots in a movement that rejected Puritan orthodoxy in New England. Although the outlook and beliefs of individual Unitarian churches can vary dramatically, most congregations retain a deep commitment to social justice, which has led them to embrace liberal positions over the years. Unitarians were among the first to ordain women, support the civil rights movement and back gay rights.

The shooting started as about 200 people watched a show put on by 25 children.

Church member Mark Harmon said he was in the first row when he heard "an incredibly loud bang." He thought the noise was part of the play, then he heard another bang and saw a woman bleeding as he dove for cover.

"It seems so unreal," Harmon said.

Church members praised Greg McKendry, 60, who died as he attempted to block the gunfire. Barbara Kemper said that McKendry "stood in the front of the gunman and took the blast to protect the rest of us."

Kemper said the gunman shouted before he opened fire.

"It was hateful words. He was saying hateful things," she said, refusing to elaborate.

"Greg McKendry was a very large gentleman, one of those people you might describe as a refrigerator with a head," said church member Schera Chadwick. "He looked like a football player. He did obviously stand up and put himself in between the shooter and the congregation."

A second victim was identified as Linda Kraeger, 61. She died at a hospital hours later, Kenner said.

Officials said Adkisson was arraigned Sunday night and faces his next court appearance Aug. 5.

Other Unitarian congregations held tearful services afterward. At a packed Westside Unitarian Universalist Church in suburban Farragut, congregants prayed, sang and consoled each other.

The shooting follows a December 2007 spree in which a man shot four staff members at a missionary training center near Denver, Colo., killing two, after being told he couldn't spend the night. About 12 hours later and 65 miles away in Colorado Springs, police say the 24-year-old man fatally shot a parishioner at a megachurch and wounded four others before killing himself.