The Oxford High School shooter has been charged with terrorism and murder, and his parents are charged with involuntary manslaughter, and now the school officials might be next in getting charged in the shooting that left four dead.
"We haven't ruled out charging anyone," Oakland County, Michigan, prosecutor Karen McDonald told CNN on Monday.
There were legal grounds to search the shooter's backpack and locker, but officials did not do so, she added.
"We don't know exactly if that weapon was in his bag, where it was," she said. "We just know it was in the school, and he had access to it."
Before the shootings, a teacher reportedly caught the student searching for ammunition on his phone during class, and a teacher found a drawing made by the suspect that included a figure getting shot, according to CNN.
The school called the eventual shooter's parents into the school and were instructed to put their son in counseling for 48 hours.
An Oxford Community School spokesperson did not respond to Axios' request for comment.
McDonald laments the tragedy had warning signs that were not picked up on in advance.
"I'm certainly not suggesting that parents should be criminally prosecuted for any bad act of a child," McDonald told CNN. "But in this case, you can't possibly look at their actions and say that they didn't have reason to believe that there was real concern about a violent act.
"All of this could have been prevented if he hadn't had access, or if just one of those parents had said, I'm concerned about what I'm seeing right now, and I also want you to know, we just bought him a gun for Christmas. And that didn't happen."