Two young people were killed and two others were wounded by a gunman who opened fire at a Christian youth mission center in Arvada, a suburb of Denver, early Sunday. The victims were members of the mission and were in their mid-20s, according to police.

Police said that they didn’t know if the gunman shot at random or picked his victims.

Susan Medina, a spokeswoman for the Arvada Police Department, said: “He entered the facility, opened fire and four of the youth inside that facility were injured,” the New York Times reports.

The two dead victims were identified by the Christian mission, Youth with a Mission, as being Tiffany Johnson, 26, of Minnesota and Philip Crouse, 24, of Alaska.

The other two who got injured were Dan Griebenow, 24, of South Dakota, who got shot in the neck, and Charlie Blanch, 22, in her leg.

Youth with a Mission has offices around the world. It teaches young Americans and international students to become missionaries in Africa, Asia and Europe.

Peter Warren, director of Denver operations for the group, said that the accident occurred just after midnight, after a Christmas banquet. The gunman came up and asked Ms. Johnson if he could stay for the night. Ms. Johnson refused him and in that moment he pulled out an automatic handgun and started to shoot.

Ms. Medina said that the gunman fled just after the shooting and they were tracking him with dogs. She said: “Unfortunately, he remains at large.”

The gunman was described as being a white man in his early 20s, possibly with a beard and glasses. He was wearing a dark jacket and a dark beanie-style skull cap, AFP informs.

Mr. Warren said: “The young man — I don’t know who he is and I don’t think they knew him — but he must be going through a lot personally in his own life to do something like this.”

The wounded were treated at hospitals in the Denver area.

Police evacuated other 45 people who were in the residence hall and put them in a location off campus.

Police also warned neighbors through calls saying that a gunman is still at large, and to remain indoors and that they should be looking for clues, like tracks in the snow.

Ms. Medina said: “This is a very extensive crime scene. We have a number of people to interview.”

The mission’s website said:  "It is with great sadness that we report the shooting death of two staff members at our YWAM Denver (Arvada) training location. Please pray -- for the families who are on their way to Denver -- for the critically injured young man undergoing surgery today -- for the staff and students who have been evacuated to another location -- for the apprehension of the gunman who fled the scene.”