OXFORD TOWNSHIP, Mich. (NewsNation Now) — The parents of a teenager accused of killing four students at a Michigan high school were summoned to discuss his behavior just a few hours before the violence, a sheriff said.

The disclosure was made Wednesday as Ethan Crumbley, 15, was charged as an adult with two dozen crimes, including murder, attempted murder and terrorism for a shooting Tuesday at Oxford High School in southeastern Michigan. The charges came hours after authorities reported the death of a fourth teen.

Oakland County Sheriff Michael Bouchard told reporters at a Wednesday news conference that the boy’s parents had been summoned to the school the day before and the morning of the shooting. Bouchard wouldn’t discuss details of the behavior school officials were concerned about but said Crumbley was at the meeting. Crumbley remained in school after the meeting.

“There is nothing that he could have faced that would warrant senseless, absolutely brutal violence on other kids,” he said.

Investigators found that he had recorded a video the night before the bloodshed in which he discussed killing students, Lt. Tim Willis of the Sheriff’s Office said.

Bouchard said three victims were still hospitalized, including two 17-year-old girls in critical condition. Two 14-year-old boys with gunshot wounds are also recovering in the hospital. One has been upgraded to serious condition, and Bouchard said the other one was “stable.”

Prosecutor Karen McDonald did not reveal a possible motive for the shooting. However, she said prosecutors are “confident” they can show the crime was premeditated.

“There is a mountain of digital evidence. Videotape, social media, all digital evidence possible,” she said.

Bouchard said their understanding of the shooting was “still evolving.” He said their investigation of the scene, which went until 5:30 a.m. Wednesday, revealed the shooter actually had 18 live rounds remaining, more than the seven they initially revealed.

In court,assistant prosecutor Marc Keast said Crumbley entered a bathroom with a backpack and came out with a semi-automatic handgun, firing at students while moving down the hallway. 

The four students who were killed were identified as 16-year-old Tate Myre, 14-year-old Hana St. Juliana, 17-year-old Madisyn Baldwin and 17-year-old Justin Shilling, who died Wednesday.

Bouchard said Myre died in a patrol car as a deputy tried to get him to an emergency room.

The boy’s father on Friday bought the 9 mm Sig Sauer used in the shooting, Bouchard said. He did not know why the man bought the semi-automatic handgun, which his son had been posting pictures of and practicing shooting, Bouchard said.

Undersheriff Mike McCabe said the student’s parents advised their son not to talk to investigators. Police must seek permission from a juvenile’s parents or guardian to speak with them, he added.

Bouchard said that the previous threat to Oxford High School was investigated and deemed “non-credible” in an interview with NewsNation.

“There’s been a great deal of misinformation on social media, we actually investigated a possible threat earlier last month in that particular school district and deemed it to be not credible,” said Bouchard on “Morning in America”. “In fact, we ran it down and it came from an individual not only not in that school district, but not even in our state. And so there was a dismissal of that particular threat.”

At a Wednesday news conference, Bouchard slammed social media sleuths who he said were sharing videos they claimed were of the shooter, but were unrelated and did not feature anyone involved. One of the videos being shared was traced to an incident in Georgia.

“It’s costing us a great deal of resources [to investigate these videos] and it’s causing the victims more harm and more hurt,” Bouchard said.

School administrators posted two letters to parents on the school’s website earlier this month, saying they were responding to rumors of a threat against the school following a bizarre vandalism incident.

According to a Nov. 4 letter written by Principal Steve Wolf, someone threw a deer head into a courtyard from the school’s roof, painted several windows on the roof with red acrylic paint and used the same paint on the concrete near the school building.

Without specifically referencing that incident, a second post Nov. 12 assured: “There has been no threat to our building nor our students.”

McCabe downplayed the significance of the situation in early November, which he said was “absolutely unrelated” to the shooting. The incident prompted school administrators to post two letters to parents on the school’s website, saying they were responding to rumors of a threat against the school but had found none.

Bouchard said the student in custody in the shooting had no previous run-ins with his department, and he was not aware of any disciplinary history at school.

“That’s part of our investigation to determine what happened prior to this event and if some signs were missed, how were they missed and why,” he said.

The district said in a statement that all schools would be closed for the rest of the week.