All I know is if police are telling the truth that they don't know, and they do NOT make an arrest within a couple weeks after the autopsy comes back, there is going to be a lot of outrage IMHO. People are going to want to know things like, why didn't they search the whole RV lot by going through all of the RVs, and about 100 other things like that and the police are going to have an insane amount of pressure on them, and I think it's really smart for all those kids to be getting lawyers right now like a previous poster mentioned.
There's not too many good motives for taking the phone:
1. a mugging, but wallet would also have to be taken presumably, also I don't think this is a mugging anyway
2. the phone incriminates the murderer somehow, phone records or texts, though you'd think kids would be savvy enough to know that police can find that info, but maybe policw ouldn't be able to get the CONTENTS of texts without the phone.
3. it just fell out and got lost if the body was being moved (if they don't think he was killed there)