Your part right. The police require reasonable suspicion of unlawful activity to require someone to stop and speak with them, or submit to even temporary detention. Given that the officer has reasonable suspicion, they can make the stop and require the pereson to hand over their weapons, which are to be returned when the stop is over, if no law violation has been shown to have been involved. No arrest can be conducted without probable cause and it appears this officer manufactured it, which is supported by the apparent fact that the officer reduced the charge later. Not a shining moment for the cop. And interrogating the boy when the boy was counseled by his dad to not talk, was also a no no.