Suggestions?

For the last couple of weeks we've been noticing a lot of dog poop accumulating on our lawn and the one next to ours. Even though I've noticed that no one else in the neighbourhood walks their dog, Dan and I religiously do and so we KNOW it isn't Chloe's poop. I've talked to other neighbours and ensured them that it isn't our dogs poop. I've had my suspicions about a big black dog that lives a couple of doors down but didn't want to accuse anyone if it wasn't. Sure enough, last night I caught the dog pooping on our lawn. It is so gross. Really. There's about 20 spots on the lawn next to ours (it borders our driveway) and about 10 now on our lawn. Big black dog poop too so it's not such a small little pile. This dog is an old dog and doesn't move much (Chloe wagged her tail right in his face while she was in the middle of heat and he didn't do a thing).
So my question is, what do we do about it? There's no way I'm going to pick it up myself although I've been tempted to since there's one right where you would step getting out of the car. Dan, of course, wants to throw it on the guy's doorstep and yell at him. I just want to keep the peace. Besides, the people are kind of sketchy. I'm actually a bit afraid of them so I don't want to start a feud.
What would you do? I really don't want to just leave it.
If I don't get some good responses soon I'm going to post some pictures with this post. :)