I still don't believe it's money in that suitcase. Why would villains pay a random homeless person anything? It could actually cause them more trouble to pay. Money can be traced, so it's a loose end should the corruption in the city actually fail to some degree. Furthermore, if some goons got the money from their superiors for this "reward", why wouldn't they just take it for themselves? What is the hobo going to do? Sue them? Villains also easily think others are similar to themselves: once you get the tab open, you will want to cash in more. So, they would likely expect Walker to try to find a way to squeeze more money out of them in the future, through blackmailing or similar methods, if they did anything to indicate it could work, like actually giving the reward to him would do.
But then again, we haven't really seen a single intelligent character in this story so far (that we would be aware of), so who knows.