The Oxford Community School District denied Michigan Attorney General Dana Nessel's offer to conduct a third-party investigation into the Nov. 30 school shooting that left four students dead and seven others injured, according to Nessel's office.
The attorney general said Monday she was "extremely disappointed" that the school district declined her offer to "devote the full resources of the Department of Attorney General to review the events leading up to and on Nov. 30."
"This tragedy demands a united effort from all of us who serve the Oxford community," she said in a statement. "Despite this outcome, my department will continue to support the ongoing criminal investigation in Oakland County and looks forward to meeting with parents, students and teachers when they are ready to share their thoughts. To that end, we also remain committed to evaluating opportunities for our department to ensure that students in Oxford – and across Michigan – receive the protection they deserve and that guns are kept out of our schools."
Oxford Community Schools Superintendent Tim Thorne announced on Saturday that the school district had launched a third-party investigation into the tragedy.
"It’s critically important to the victims, our staff and our entire community that a full and transparent accounting be made," Thorne said. "To that end, I’ve asked for a third-party investigation be conducted so we leave no stone unturned, including any and all interaction the student had with staff and students."
The announcement came after the Oakland County Prosecutor Karen McDonald said on Friday there were warning signs from the student charged in the school shooting.
Shooting suspect Ethan Crumbley is being charged as an adult with murder, terrorism and other offenses. A teacher caught Crumbley searching for ammunition on his phone during class. A teacher also caught him drawing disturbing images of a bullet and a person who appeared to have been shot, according to McDonald.
"On the morning of Nov. 30, a teacher observed concerning drawings and written statements that have been detailed in media reports, which the teacher reported to school counselors and the Dean of Students. The student was immediately removed from the classroom and brought to the guidance counselor’s office, where he claimed the drawing was part of a video game he was designing and informed counselors that he planned to pursue video game design as a career," Thorne wrote.
Thorne added that there was no indication the student would harm other individuals.
"At no time did counselors believe the student might harm others based on his behavior, responses and demeanor, which appeared calm," the letter said.
Fox News' Adam Sabes contributed to this report.