At least two students have been confirmed wounded after a gunman fired his shotgun at the Arapahoe High School in Centennial in Colorado.

According to County Sheriff Grayson Robinson, the gunman, who police did not name, is a student who entered the campus looking for a teacher to get revenge. The teacher was then informed about the possible threat and quickly left the building. One of the students confronted the armed man but was shot and rushed to the Littleton Adventist Hospital. Another student, whose identity was not immediately released, was found with minor injuries and may not have been hit by bullets.

Police came to the rescue, put the place in locked down but was surprised to see that the threat has already ended. The authorities found the still unidentified suspect dead from what appears a self-inflicted gunshot wound.

Based on initial reports, heavily-armed police officers trained in "active shooter" scenarios stormed the school and ordered students to step outside with their two hands over their heads. The kids were asked to walk to an area church to meet their worried but contained parents.

Greyson confirmed that they "have not been able to locate a second suspect, but that's part of our ongoing investigation.

This is probably the nth time that a psychotic gunman disturbed Colorado. In 1999, Columbine High School in nearby Jefferson County was attacked by two students and took the lives of 13 pupils and staff before killing themselves to death. 

Another awful shooting incident that gripped Colorado was the 2012 Aurora shooting that killed 12 innocent people and injured 70.

What's even worse is that this shooting incident took place a day before the anniversary of the tragic Sandy Hook Elementary School shooting in Newtown, Connecticut wherein a gunman killed 20 kids and six adults.