Four persons, including a gunman, were killed and six injured in two shootings at a church and a missionary training centre within 12 hours of each other in the United States' Colorado state. This incident comes just three days after a firing spree by a youth left nine people dead in a Nebraska shopping mall.
A gunman shot dead two staff members of missionary training centre Youth for Mission and injured two others in Arvada at 12:30 am local time on Sunday after being denied permission to spend the night there. He then fled the scene on foot.
Just 12 hours later, another man was shot dead and four others injured by an attacker near New Life church, before he was killed by a security staff in Colorado Springs, about 112 kilometers away from the first shooting site.
The assailant, who matched the description of the Arvada attacker, opened fire as soon as about 7,000 worshippers completed their late morning service.
Arvada police chief Don Wick said they had reasons to believe that the two shootings may be related, but refused to confirm if the same gunman, said to be a white male in his 20s, was involved in the incidents.
A young woman and man were among those killed, while another, who was shot in the neck, was in critical condition. The fourth victim was hit in the leg, the police said.
In Colorado Springs, police chief Richard Myers praised the courage of the security man who shot dead the gunman, saying he probably saved many lives.
The Colorado church, which is said have a membership of 10,000, despite a controversial history as its founder was ousted in 2006 after admitting to 'sexual immorality', was evacuated after the police found several suspicious devices and searched the huge campus room by room.
The two shootings come within four days of a youth killing eight people before turning the gun on himself in a crowded shopping mall in Omaha, Nebraska.
While recent shooting rampages in the US have reignited the debate over its lax gun control laws, Sunday's shootings at religious places have evoked outrage and fear among the congregations of possible copycat incidents.
In Los Angeles, the police arrested a 21-year-old university student on Saturday night in connection with an online threat to shoot people on campus. Carlos Huerta was arrested near his apartment on Loyola Marymount University campus for allegedly posting a message on a chat board that he would shoot and kill as many people as possible on campus before being killed himself by the police.
