Details of the exchange came from depositions provided by school officials after several families sued the Oxford Community School District in federal court last year.
According to Hopkins' testimony, Johnson said, the counselor commented on the backpack's weight after the teacher gave it to him.
After returning to the meeting, Hopkins gave the bag to Ejak, who passed it to the teen.
Johnson said some school officials missed other red flags, including an incident Nov. 29 where the suspect's teacher saw him looking at images of bullets on his phone.
After the teacher began reviewing his classwork and noticed his interests "leaned toward the violent side," Johnson said, she reported what she found to other school officials, including Hopkins.