

Murder is killing with malice. Assassination is killing for political capital. There can be crossover but it isn’t necessary.
Take a head of state — not strictly a current one, not wishing here. Just as an example. He’s giving a speech, it’s an assassination. You caught him in bed with your wife and shot them both — that’s murder.
They used to say the rewards was for information leading to the conviction. If they don’t get a conviction, the reward is forfeit by default.
People are still gonna try though. They just have no legal recourse if the reward is not paid.