Police Intuition
Kaycee mentioned that the infant was given a diagnosis of respiratory distress syndrome, which ultimately led to him passing away at such a young age. This was ultimately the reason for his death. The cops did all in their power to convince themselves that what they were hearing was true.
Nevertheless, they just couldn’t bring themselves to accept what they were hearing as fact. Because the officers did not currently have any evidence in their possession, they were forced to let the suspects go because they had no other option. Despite this, members of the law enforcement community went to Lang’s residence the very next day with a search warrant to investigate that location.