OXFORD TOWNSHIP, Mich. (NewsNation Now) — Oxford Community Schools leaders have declined requests for interviews, despite calls from the community demanding answers about why the student charged in last week’s shooting was allowed to go back to class after a disturbing note he had written was discovered.

On Friday, the head of the district released a letter detailing its version of the events leading up to the tragedy that left four students dead and several people injured.

According to the letter the superintendent sent to parents Friday, a teacher reported Ethan Crumbley’s disturbing drawing of a gun pointing to the words “The thoughts won’t stop. Help me,” to the school counselors and the dean of students Tuesday. Crumbley was brought to the guidance office.

His parents were called in, but the district says they refused to take him home and he was returned to class.

In the letter to parents, the superintendent defended school staff, saying the counselors made a decision based on their experience and did not have all the facts we know now.

NewsNation’s Brian Entin has tried calling and emailing school board members and the superintendent. He also attempted to go to the administrative office, but the doors were locked.

Michigan Attorney General Dana Nessel told Entin on Sunday that “anything is possible” when it comes to potential criminal charges for the school officials who were made aware of the studen’s alarming behavior.

“I don’t want to jump to any conclusions because again, we don’t have that information at this point,” Nessel said during a one-on-one interview. “But that is a big part of the investigation. People want to make sure that these questions are answered.”

Nessel is offering to do an independent investigation into what led up to the shooting.

Hunter Pollack, who lost his sister Meadow in the Parkland shooting almost four years ago, says families in Oxford must demand accountability.

“These school officials and these parents have blood on their hands because they knew this kid was going to blow and they let him go back to class,” Pollack said. “Why didn’t they search his backpack? Why didn’t they bring a police officer into that meeting so the police officer could assess the student for himself?”

Crumbley has been charged as an adult with murder and terrorism, along with other crimes. His parents were arrested early Saturday morning after a manhunt led police to a Detroit warehouse. The parents’ car was spotted outside.

“They are in our jail,” Sheriff Michael Bouchard said. “All three of them. The son and both parents segregated individually in isolation.”