A Colorado man opened fire during a birthday party, killing six people before committing suicide on Sunday, police said.

The incident occurred shortly after midnight in a mobile home park on the east side of Colorado Springs. Police who arrived at the scene found the bodies of six adults and a severely injured man who died after being transported to the hospital.

Mass Shooting

Authorities suspected that the shooter was the boyfriend of one of the female victims at the birthday party. Many people attended the event, including friends, family, and children. The gunman allegedly walked inside and quickly opened fire before killing himself.

Police said the event was held for one of the victims. One neighbor woke up to the sound of gunshots nearby. “I thought it was a thunderstorm. Then I started hearing sirens,” Yenifer Reyes said.

Police officers brought out the children inside the trailer and placed them into a patrol car. They said one of the kids was “crying hysterically.” Authorities said none of the children were hurt during the incident and have been given over to relatives, India Today reported.

As of Sunday, officials had not yet revealed the identities of the suspect and the victims. They have not yet identified a motive for the shooting. “My heart breaks for the families who have lost someone they love and for the children who have lost their parents,” Colorado Springs Police Chief Vince Niski said.

Officials recorded the incident as Colorado’s worst mass shooting since March 22 when a lone gunman killed 10 people at a Boulder supermarket. “The tragic shooting in Colorado Springs is devastating, especially as many of us are spending the day celebrating the women in our lives who have made us the people we are today,” Governor Jared Polis said on Sunday.