DOUGLAS COUNTY, Colo. (CBS4) – Testimony continued Thursday in the hearing to determine if one of the suspects in the STEM School Highlands Ranch shooting should be tried as an adult. On day four, both a counselor and a teacher testified about Alec McKinney’s, 16, behavior in school.

(credit: CBS)

READ MORE: Fight Between Passenger & American Airlines Flight Attendant Causes Flight To Be Diverted To Denver International Airport

The counselor shared a Safe2Tell tip saying McKinney joked about suicide and cutting himself in November 2018, six months before the shooting on May 7. The counselor thought it was serious enough to call police and McKinney was taken to a hospital. But he was released the next day.

(Photo by Tom Cooper/Getty Images)

McKinney’s English teacher testified that he often missed class and struggled to have friends at first. She did worry he would harm himself but never thought he would harm others.

Alec McKinney (credit: Instagram)

A Douglas County District Court judge has already ruled there is sufficient evidence for the case to move forward to trial, but it is up to McKinney’s defense to argue why he should be tried as a juvenile.

READ MORE: Some CU Boulder Students Believe This Halloween Won't Be As Problematic With COVID Cases

Thursday, the prosecution called several witnesses to paint a picture of the damage McKinney caused the day of the shooting, explaining why he should continue to be treated as an adult.

RELATED: STEM School Shooting Suspect Alec McKinney Wanted Students To ‘Live With This Fear’

Devon Erickson makes a court appearance at the Douglas County Courthouse on May 15, 2019. (credit: Joe Amon-Pool/Getty Images)

On Monday, a detective testified that Devon Erickson, the second suspect in the school shooting, wrote “the voices win” in red nail polish on a closet wall in Erickson’s house when Erickson and McKinney were there just hours before the shooting.

The detective said Erickson told investigators McKinney was the leader of the plans for the shooting, and said he only participated in the shooting, because he was scared McKinney would hurt him. However, the detective said Erickson had plenty of chances to call for help, and he didn’t act on those opportunities, explaining there were also emergency buttons in the school that Erickson saw, and could have pushed, moments before the shooting. Detectives believe both McKinney and Erickson were willing, and not coerced, participants.

MORE NEWS: Ball Arena & Paramount Theater To Require Proof Of Vaccination Or Negative COVID Test

Proceedings are expected to continue through Tuesday, November 26, in Douglas County District Court.