The Rise and Fall of Jesus Christ

Peter was the same guy who had denied knowing Christ. If Jesus hadn't been raised from the dead, why would Peter be doing this? He wasn't telling them something that was unknown. These people were all alive during these events and they could have easily verified whether it happened or not. So he tells them, you know what happened. And I've never heard a good explanation for why these men would have said these things if they weren't true.