A gunman opened fire Sunday in a training center for young Christian missionaries outside Denver, Colorado, killing two people and wounding two others, police said.

A gunman entered the dormitory in Arvada, Colorado, early Sunday.

The lone gunman walked into Youth With a Mission, began shooting and then ran away, according to Susan Medina of the Arvada Police Department.

A man and a woman, both in their mid-20s, were killed, Medina said. Two men, ages 22 and 23, were wounded, but Medina would not provide their conditions.