In the article Police suspect, Kate Levine discusses agreements that exist to protect many US police forces against the same interrogation methods they use on the rest of us.
… police have dealt themselves special protections from police questioning based on their knowledge of what protections a suspect needs most when facing interrogation. Meanwhile, the police continue to argue that failing to use these selfsame tactics on other suspects will hamper their ability to catch and convict dangerous criminals.
These protections are known as Law Enforcement Officers’ Bills of Rights (LEOBORs).
LEOBORs take the form of state statutes or negotiated jurisdictional agreements and provide affirmative interrogation protections for police suspects that go far beyond the Fifth and Fourteenth Amendment protections that other suspects receive. For instance, LEOBORs often provide that police suspects may be questioned only during the day; that they may be questioned only by a limited number of interrogators; that they must be given time to attend to their personal needs; that they may not be threatened, subjected to abusive language, or induced to confess through untrue promises of leniency; and that their choice to inculpate themselves must not be conditioned on losing their job or benefits.
As Levine points out, LEOBORS have the perverse effect of giving greater protection from manipulation and false confession to the least vulnerable:
[LEOBORS] further invert the purpose of constitutional protections by giving already sophisticated suspects an extra layer of rights that the rest of us do not receive.