Police in front of a missionary training facility in Arvada, Colorado, 09 Dec 2007

Police say they believe a single gunman was responsible for killing four people in two shooting incidents at religious facilities in the western U.S. state of Colorado.

Investigators said Monday Matthew Murray shot two people to death at a missionary training center in Arvada shortly after midnight Sunday. About 12 hours later and 100 kilometers away, officials said Murray killed two teenaged girls who were leaving a church service in Colorado Springs.

Five others were wounded in the two shootings.

An armed security officer with the New Life church shot and killed Murray. Police said Murray's backpack contained more than 100 rounds of ammunition. Church leaders said the security officer prevented greater loss of life.

Police said Murray had been part of the "Youth With a Mission" program in Arvada several years ago, but had been thrown out of the school for unknown reasons.

Some information for this report was provided by AP.