The following scenario addresses potential contractual disputes involving Mary and Bob's claims to a reward. Please read carefully and respond to all of the following prompts:
The Police Commissioner is under pressure to solve a murder and offers $100,000 for information leading to an arrest and conviction of the culprit. Mary suspects her neighbor, Phoebe, is the guilty party and calls Bob, a friend and police officer, with her suspicions. Bob decides to check out Mary's tip on his off-duty time, hoping to get the reward for himself. When Bob visits Phoebe, she unsuccessfully resists arrest, though Bob is severely injured. Phoebe is ultimately convicted of the murder and assaulting Bob. Mary insists all the reward money belongs to her. From his hospital bed, Bob insists that he deserves the reward or at least half of it.
What type of contract is created by the Police Commissioner's offer of a reward?
Does Mary need to testify to entitle her to the reward money?
Will Bob be able to successfully claim all or a portion of the reward?
What is the policy consideration behind the relevant rule in this case?