Curt James Brockway, 39, tried justifying his actions as the crowd began chastising him for the attack.
'He said (the boy) was disrespecting the national anthem so he had every right to do that,' Hennick explained.
The boy - identified as a 13-year-old by Mineral County Sheriff Mike Boone - was taken to a local hospital before he was flown to the Sacred Heart Children's hospital in Spokane.
Brockway was arrested at approximately 11pm on Saturday by Mineral County Sheriff's deputies.
State DOJ records indicate that the man has a history of being a violent offender and he was in the midst of serving a 10-year probation sentence for an assault with a weapon charge in 2010.
His arraignment is scheduled for August 14 at 10am.