Oxford, Michigan CNN  — 

Two teachers separately reported concerning behavior from sophomore Ethan Crumbley starting the day before the fatal Michigan high school shooting he’s accused of – prompting two meetings with him, including one with his parents just hours before the killings, a sheriff said Thursday.

Crumbley, 15, was charged as an adult Wednesday with terrorism, murder and other counts in connection with Tuesday’s shooting that killed four students and wounded seven other people at Oxford High School north of Detroit.

The first behavioral report came Monday, when “a teacher in the classroom where he was a student saw and heard something that she felt was disturbing,” Oakland County Sheriff Michael Bouchard told Brianna Keilar on CNN’s “New Day.”

“And they had a counseling session about it with school officials, and a phone call was left with the parents,” he said.

Then on Tuesday – hours before the shooting – “a different teacher in a different classroom saw some behavior that they felt was concerning, and they brought the child down to an office, had a meeting with school officials, called in the parents, and ultimately it was determined that he could go back into class.”

Authorities say Crumbley soon opened fire outside a school bathroom. He moved through a hallway at a “methodical pace,” prosecutors said, shooting at students in hallways and classrooms before surrendering in what’s become the deadliest shooting at a US K-12 school since 2018 and the 32nd on such a campus since August 1.

Bouchard declined to detail what the teachers’ concerns were, adding that his department was “never informed of either meeting prior to the shooting or that there were any concerns about behavior.”

When asked why Crumbley was allowed to return to class on Tuesday, Bouchard said: “That will all be part of the investigation, in terms of what they thought, and why they thought that that was the right step.”

At a later news conference, in response to a question from CNN, he said: “In light of where we are today, certainly we would have liked to have been part of that discussion and information.”

When pressed by CNN, the sheriff declined to speculate as to whether that information could have prevented the shooting.

In a video statement Thurday, Oxford Community Schools superintendent Tim Throne said no disciplinary action was warranted against Crumbley following the meeting with him and his parents the morning of the shooting.

“There’s been a lot of talk about the student that was apprehended. That he was, you know, called up to the office and all that kind of stuff. No discipline was warranted. There are no discipline records at the high school. Yes, this student did have contact with our front office. And yes, his parents were on campus November 30th,” Throne said.

Throne praised students and staff for their response, stating that some administrators performed CPR and said the students “did exactly as they had trained.” He will be meeting with the parents of the four students who died, he said, adding that he will answer all questions at a later time but “this is as much information as we can give you today.”

Cell phone videos refer to killing students, officials say

After the shooting, investigators found two videos on Crumbley’s cell phone – made the night before the shootings – in which he talked about shooting and killing students at the high school, sheriff’s Lt. Tim Willis said at Crumbley’s arraignment Wednesday.

Another piece of evidence investigators uncovered is a journal that was in Crumbley’s backpack that detailed his “desire to shoot up the school to include murdering students,” Willis said.

The weapon authorities said was used in the shooting, a 9mm Sig Sauer SP2022 pistol, was purchased by Crumbley’s father four days before the shooting, Bouchard said Tuesday.

A photo of the pistol believed to have been used in the shooting was posted to an Instagram account days earlier, a law enforcement source with direct knowledge told CNN.

The Oakland County Sheriff’s Office believes the account belongs to Ethan Crumbley, the source said.

“Just got my new beauty today. SIG SAUER 9mm,” reads the caption under the post, which is no longer available online but was shared widely on social media.

A photo of the gun believed to have been used in the Oxford High School shooting Tuesday was posted to an Instagram account days before the incident, a law enforcement source with direct knowledge tells CNN.

CNN has attempted to reach Crumbley’s parents and is attempting to identify their attorney and a new attorney for their son.

Asked about Crumbley’s parents’ knowledge of what their son was writing or recording before the shooting or his accessing the new weapon, Bouchard on Thursday told CNN: “We don’t have any information that they knew that this was a path he was headed. But … that’s very much an active investigation.”

Oakland County Prosecutor Karen McDonald said at a news conference that her office is determining whether Crumbley’s parents should be charged and she expects an announcement by Friday afternoon.

McDonald has said that firearm ownership comes with legal responsibilities such as securing the gun properly and ensuring ammunition is kept separate.

CNN has pressed the prosecutor to speak on whether evidence was recovered to support potential charges and which charges are being considered. The prosecutor has declined to go into detail, citing the investigation.

Bouchard told CNN’s Wolf Blitzer on Thursday evening that detectives were still working on that aspect of the case while pointing out that neither the suspect nor his parents were talking to law enforcement.