I get what you are saying and its very frustrating. I'm sure there are many times law enforcement wants to get a warrant, arrest someone or do something because they just know the person is troubled or will do something and they are prevented from doing so. Its just a tough balancing act and I'm not sure there is a quick or clear answer. I know if I was a parent that lost a child I would be angry and be asking questions as to why they didn't arrest or detain him. Its just heartbreaking all the way around and I'm sure for local and federal authorities that it tears them up the same as it does for everyone else if not more.