A 15-year-old boy was arrested by Seattle police on Saturday night after a witness saw him armed with a gun at Alki Beach, according to the Seattle Police Department.

At about 8 p.m. Saturday, police responded to a report of a person armed with a large gun at Alki Beach.

When officers arrived, they searched and found him, however, he ran away.

The person was quickly detained with the gun near the intersection of 58th Avenue Southwest and Alki Avenue Southwest.

The 15-year-old boy was arrested for unlawful possession of a firearm and booked into the King County Child and Family Justice Center.