As someone who conduct investigations we reach out to forensic cyber specialists, there will be some in your area, they are usually part of larger investigation units outside law enforcement. This would be if there was a serious concern for the youth or child. You an also reach out to the local cyber crimes teams, they usually have some good info for parents. As a parent my kids had to sign a contract for use of their cell phone, this included the need for us to have passwords and approve any apps before they were installed. Of course we had a privacy and respect claise, that we would not sneak onto their device to spy on them or track them. This really helped up be open, they asked questions and when something went wrong for them or their friends they knew they can come to us first. This was very important and helped catch a guy for international cyber crimes who was targeting a friend. Good Luck. It is not easy going these days