I just rescued a rabbit

I live in an apartment complex, and today I noticed a rabbit outside in a wire cage. The door was open--didn't even shut, and the rabbit had a leash on to keep it attached to the cage. His/her water was in a mug, which I doubt he could even reach, and he was sitting on moldy hay. So I took him. The apartment obviously had several kids, so I don't think they paid that much attention to him. I'm surprised something hadn't attacked him already, especially since the cage was right on the ground. I've gently bathed him with water to wash off the grime and a few encrusted poops, no soap since I don't have any animal friendly ones. Right now he has water and is running around in my bathroom with the door closed, no exposed wires or anything. I'm going to get him some food and make a C&C cage as soon as possible. If the people miss him and come looking for him, or if anyone saw me, I'm going to cover myself by saying that his leash had broken and no one looked home (it was dark) so I took him in for the night. I'm hoping they don't miss him and I can keep him. I had rabbits as a kid so I'm not 100% clueless, though of course they didn't have a C&C cage. I talked to my mom a little and she agrees that I did the right thing, I just feel all jittery, like I've broken the law or something. I've never done anything like this before and could use a little reassurance.