COLORADO SPRINGS, Dec. 10 (UPI) -- A security plan implemented after a Denver area shooting saved "hundreds of lives" at a Colorado Springs megachurch, a report says.

A parishioner of the New Life church acting as the security guard shot and killed an armed gunman in the second of two incidents Sunday that left five people dead.

The gunman, identified as Matthew Murray, 24, of Arapahoe County, shot and killed two teens, identified by police as sisters Rachel Works, 16, and Stephanie Works, 18, before entering the building, CNN reported Monday. A 51-year-old man described as a relative of the teens was also shot but remains hospitalized in good condition.

The security guard used her personal weapon to shoot and kill the gunman after he had made it no further than 50 feet inside the building, , the Rev. Brady Boyd said.

"She probably saved over a hundred lives," he added.

Boyd said the gunman had no connection to the church.

"He simply showed up on our property yesterday with a gun, with the intention of hurting people, and he did," Boyd said.

He said New Life took extra precautions after hearing of a shooting in nearby Arvada in which two people were killed after a gunman was refused lodging at Youth With a Mission live-in Christian missionary center. Police are trying to link the two incidents.