The FBI could see through the fog and identify the problem:

From PMPT pb page 499 (The Quantico Presentation)

The police then mentioned the Ramseys' behavior immediately after the body was found: the fact that John Ramsey was ready to fly to Atlanta with his wife and son and leave his daughter's body - and the investigation into her murder - behind; the refusal to cooperate with the police; and the hiring of criminal attorneys. In reply, the FBI pointed out that no two people respond to trauma and grief the same way, and that the police should not overanalyze what they had observed. Most of the time, the parents of a victim are all over the police. "Why the hell haven't you caught my child's killer?" "What's going on? I want to know everything." In this case, the police had to acknowledge that it was their own commander's actions that led to the long postponement of the parents' interviews.