While being restrained after the shooting at a Virginia school, the boy is said to have admitted “I did it”, adding “I got my mom’s gun last night”.
His teacher, Abigail “Abby” Zwerner - who survived - filed a $40m (£31.4m) lawsuit earlier this year.
Using his mother’s gun, the boy shot his first-grade teacher, Ms Zwerner, in the hand and chest on 6 January at Richneck Elementary School in Newport News, Virginia.
After the shooting, Ms Zwerner told police at hospital that she saw the child standing by his desk when he “pulled a firearm out of his jacket pocket and pointed it” at her, according to the newly released documents.
Amy Korvac, a reading specialist at the school, heard the gun shots and restrained the student until police arrived.
In Ms Zwerner’s lawsuit, filed in April, she accuses school officials of gross negligence for ignoring warning signs and argues the defendants knew the child “had a history of random violence”.