Doesn’t require one in this circumstance. It’s judged on contractual standards which includes oral agreements. What Steele is talking about occurs after charges are laid.

Steele screwed up. This is judged based on contractual standards which includes verbal agreements. His lawyer is dead. Steele knew about the agreement 3 months before he lay charges.

Forget your mind. Plea deals occur after charges are laid. The deal was to never lay charges against Cosby.

Wrong. This is a settled question in Pensyvania. Government official’s promises, whether it's a law enforcement officer or a prosecutor, who makes a promise not to prosecute is binding. Furthermore, Castor was the DA , head of his office.

No. A government officials promises are binding on the office. The office cannot later renege.