This isn't a situation I'm in, but rather something I'm curious about.
If a private person (outside of any position of authority) is bribed to keep an illegal act they witnessed secret, but chooses to report the crime to the police regardless, is that person able to keep the bribe?
I know the contract is compromised by the criminal element, but does that negate the criminal portion of the agreement (letting the witness keep the bribe), negate the entire contract (requiring the bribe be returned to the criminal) or cause another outcome (bribe is surrendered to the state)?
Likewise, if the criminal informs police that they bribed the witness in exchange for silence, even though the witness reported the crime anyway and cooperated fully, is the witness thereby guilty of any crimes themselves?