The man who killed four people at a church and missionary training center died of a self-inflicted shotgun wound, police said Tuesday.

Matthew Murray, 24, was struck multiple times by a security officer at New Life Church Sunday but died after firing a single shot at himself, the El Paso County Coroner's Office concluded after an autopsy.

Murray was shot by volunteer security guard Jeanne Assam, whom police and church leaders credited for her bravery with averting a greater tragedy.

Assam, an ex-Minneapolis police officer, said her faith allowed her to remain steady under pressure.

"It seemed like it was me, the gunman and God," she said, her hands trembling as she recounted the shooting during a news conference.

Murray posted a warning on a Web site prior to his killing spree.

According to the Denver Post, Murray copied from the manifesto of Columbine High School shooter Eric Harris in his post on a site for people who have left organized religion.

"You christians brought this on yourselves," Murray wrote. "I'm coming for EVERYONE soon and I WILL be armed to the @#%$ teeth and I WILL shoot to kill.

"Feel no remorse, no sense of shame, I don't care if I live or die in the shoot-out. All I want to do is kill and injure as many of you as I can especially Christians who are to blame for most of the problems in the world."

The Denver Post reported that the only change of substance Murray made to Harris's writings was to replace the name of Harris target, classmate and neighbor Brooks Brown, with "Christians who are to blame for most of the problems in the world."

Police said Murray had been thrown out of Youth With A Mission, a missionary training school in Arvada, a Denver suburb, which was the site of the first shooting. There he killed Tiffany Johnson, 26, and Philip Crouse, 24.

Colorado Springs police said the "common denominator in both locations" was Youth With a Mission. The training center maintains an office at the 10,000-member New Life Church in Colorado Springs.

Murray was home-schooled by his family and raised in what a friend said was a deeply religious Christian household.

Murray's father is a neurologist and a leading multiple-sclerosis researcher.

Five people -- including Murray -- were killed and five others wounded Sunday in the two eruptions of violence 12 hours and 65 miles apart.

Police said a weapon found at the church was forensically linked to shell casings left behind at the missionary school.

The victims at New Life Church -- sisters Stephanie Works, 18, and Rachel Works, 16 -- were involved with a summer outreach organized by New Life Church and a ministry of YWAM, according to a statement released by Youth With A Mission.

The statement said that Murray was "briefly a student at the YWAM Arvada training centre in 2002."

Murray was enrolled in a Discipleship Training School but did not complete the program, which is a 12-week classroom course followed by a 12-week field assignment.

"Murray did not complete the lecture phase of his Discipleship Training School, nor did he participate in the field assignment," the statement said. "The program directors felt that issues with his health made it inappropriate for him to do so. Murray left the Arvada training center and no one at the facility recalls that he has made any other visits or had any communication with the center since that time."