Roy Parham the man on the left, one of the detectives that helped to put the wrong man in prison. He States here that because he got a lawyer is what did it for him. He needs to read the Bill of Right and the Miranda Rights.
He also makes it sounds like Casteel would not talk to them. As you can see below Casteel did talk to them on July 11, 1988 without a lawyer.
One other thing the lawyer he hired was not even a criminal lawyer

 In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor,

and to have the Assistance of Counsel for his defence.

   1.You have the right to remain silent.
   2.Anything you say can and will be used against you in a court of law.
   3.You have the right to an attorney.

4. If you cannot afford an attorney, one will be appointed for you.

The Miranda Rights

The Bill Of Rights

Source Chatt. Times Free Press