ONE student was killed and eight students were injured in a shooting at a Colorado school in the United States on Tuesday, according to authorities.

The deceased male, who has not been identified, was 18 years old. Two suspects are in custody, Douglas County Undersheriff Holly Nicholson Kluth told reporters during a press conference. Emergency dispatchers received reports that shots were fired at the STEM School in Highlands Ranch just before 2 p.m., according to a tweet by the sheriff’s office.

Investigators believe one of the suspects is an adult and the other is a juvenile, and they are both students at the school, Douglas County Sheriff Anthony Spurlock told reporters.

The adult was identified late Tuesday as Devon Erickson, 18. Officials said they would not be releasing a photo of him “as it could jeopardize this critical ongoing” investigation.

Neither suspect was previously on the “radar” of law enforcement, Spurlock said.

Authorities do not have any information as to whether any of the injured were targeted, Spurlock said.

A struggle may have ensued between the suspects and someone at the school , Kluth said. The male suspects were not injured, Spurlock said.

The suspects got “deep inside the school” and engaged students in two separate locations, Spurlock said, adding that one of the weapons used was a handgun. Investigators believe they have located all suspects involved, he added.

The injured students, who are all at least 15 years old, were taken to area hospitals, some in critical condition, Spurlock said. Some students have since been released and have been reunited with their families, he added.

The charter school teaches kindergarten through 12th grade and has more than 1,800 students, Kluth said. More than 500 of those students are elementary age, ABC Denver affiliate KMGH reported.

Colorado Gov. Jared Polis said the state is making all public safety resources available to assist the sheriff’s office.

(SD-Agencies)