At Midnight During a Weekend, a School Alarm Went Off

At midnight during a weekend, a school alarm went off, which automatically sent a message to the local police department. Two patrol cars responded and checked all the school doors. One of the doors, while still chained, had sufficient slack for entry. The police entered through the door and searched the building. Hiding in the auditorium on a stage behind some curtains was a juvenile with his faced pressed against the wall. The officers located the juvenile and commanded him to stand up and face the wall. The juvenile complied. He cooperated with the officers and stated no one was with him, that he had just run away. The officers took the juvenile to headquarters, read him his rights, and questioned him. They discovered the juvenile, age 15, had no prior history, had a fight with his parents, and ran away. Upon facing the cold weather, the juvenile sought refuge in the school when he discovered the door was open enough for him to enter. He was unaware of a silent alarm, but when he heard the officers coming, he hid. They contacted his parents, who confirmed the boy had run away after a fight with them. There was no damage to the school. What should the officers do now?