well, it could aso be that someone looked at the evidence and said "hmmmm... a good lawyer would probably get him off. it might be cheaper for the state not to prosecute." you can expect the kid to HAVE a good lawyer.
lemme tell ya about another kid i know. he was 18, at a graduation party. the stereo was too loud, and the cops came. when they walked in they saw the boy with a beer in his hand. he was arrested, and taken to the police station and charged with public intoxication, and underage consumption. tis kid had no fancy lawyer. just legal aid. he got 6 months probation, mandatory drug and alchohol counseling (which cost $1800) plus court costs, plus victim of violent crimes compensation fee, and random urine tests during probation. and banned from obtaining a driver's license until 21. for a beer. during that time he failed a urine test for pot. they violated his probation, tacked on 18 months more, made him repreat the drug and alchohol counseling, and submit to weekly urine screen and attend an .A.A sort of program run by th state. a couple weeks before he finally finished his probation, his parole officer called him in the middle of his shift at work, and commanded him to appear and submit to a urine test. when he could not get across town fast enough on the bus, the violated his probation, gave him 30 days in a drug rehab, 24 more months probation, and 6 months of follow up drug and alchohol counseling. by the time he paid his debt to society for that beer, he was 23, and had spent over 5 grand. for a beer, at an age where he is old enough to die for his country.
EDIT: i got to thinkin about this, and i figured i should just say, it's not me, but someone i was tight with.