DENVER -- The El Paso County Coroner's Office said Tuesday that gunman Matthew Murray died from a self-inflicted gunshot wound.

The death of Matthew Murray has been ruled a suicide, the coroner said.

"It should be noted that he was struck multiple times by the security officer which put him down. He then fired a single round killing himself," the coroner said.

Murray shot himself in the head, said police Sgt. Skip Arms.

The coroner also ruled that Stephanie and Rachael Works were both killed by a single gunshot to the torso and their deaths were ruled homicides. They marked the 25th and 26th homicides of the year in Colorado Springs.

Volunteer security guard Jeanne Assam shot Murray after he entered the New Life Church Sunday afternoon. Though investigators had earlier suggested he killed himself, they credited Assam's bravery with averting a greater tragedy.

Assam, a 42-year-old former 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 Monday.

The first attack Sunday took place at Youth With a Mission, a training center for missionaries in Arvada; the other occurred about 12 hours later.

Officials said revenge was one apparent motive for the attacks. Police said Murray had sent hate mail to the Youth With a Mission center in the last few weeks after being removed from the program years ago.

In a statement, the training center said "health problems" kept Murray from finishing the program, but didn't elaborate. Murray did not complete the lecture phase or a field assignment as part of a 12-week program, Youth With a Mission said.

Authorities also believe Murray authored an anti-Christian diatribe online that closely repeated a rant by one of the Columbine killers, a newspaper reported Tuesday. (Read that story.)

The most recent post to the site, a forum for people who have left evangelical religious groups, was Sunday morning in the hours between his attacks in Arvada and Colorado Springs.

"You Christians brought this on yourselves," Murray wrote. "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 language in the post is almost identical to the text of a manifesto written by Eric Harris, one of the teens who carried out the 1999 massacre at Columbine High School.

In a search warrant affidavit, investigators said Murray attended a home-based computer school and worked at his computer for three to five hours a day for the past two years. Police said Murray's only previous brush with the law was a traffic ticket earlier this year.

His relatives said they were grief-stricken and baffled.

"We cannot understand why this has happened. We ask for prayer for the victims and their families during this time of grief," said Phil Abeyta, Murray's uncle, who read a statement from the family Monday.