Two people have been killed after a gunman opened fire at a training centre dormitory for young Christian missionaries. The man started shooting after he was told he could not spend the night there.

The incident took place at 12:30am on Sunday at the Youth With a Mission centre in Arvada, a suburb in Denver. So far no one has been arrested for the crime.

Susan Medina, a police spokeswoman said that a man and a woman were killed and two men were wounded, according to MSNBC. The four victims were all staff members at the centre according to Paul Filidis, a spokesman for Youth With a Mission.

In another incident 12 hours later, a gunman began shooting at the car park of New Life Church in Colorado Springs just after a service. One person was killed and four others were hit in the attack before the shooter was killed by a guard. Colorado Springs is 65 miles from Arvada where the first shooting took place.

The authorities in Arvada are sharing information with detectives investigating the shooting at Colorado Springs. So far, Arvada police have helped Colorado Springs serve a search warrant for a house in Englewood, 15 miles south of Denver, reports MSNBC.

The descriptions of the gunmen are reported to differ. The attacker in Arvada used a handgun, whilst the shooter at Colorado Springs used a rifle.

According to MSNBC, Arvada Police Chief, Don Wick said "there is reason to believe" that the two attacks are somehow linked.

In Arvada, the gunman is reported to have spoken with people inside the centre. When it became apparent he could not stay the night there he began shooting before leaving on foot.

It is also unknown if the gunman knew any of the students or staff at the centre or why he came to the dormitory at all.

According to MSNBC, witnesses told the police that the gunman was a 20-year-old white male in a dark jacket and a skull cap, he may also have had glasses or a beard.

Police used dogs to search the area through the night and local residents were informed to keep watch and look for footprints in the snow during the night.

The two people killed were Tiffany Johnson, 26, and Philip Crouse, 23. The injured men are both in their twenties. One of them is in hospital in critical condition, say the police.