If I remember right Rossi is 6 mos. right? He's still a puppy & depending on how long you have had him and how he was trained prior to you getting him, could have something to do with it. It also sounds like he may be suffering from separation anxiety a bit.
First thing you need to do is get some Nature's Miracle, it's a spray that you can use that will totally eliminate any odors left from Rossi peeing..Start from scratch, start taking him out every hour or so, when you go out the door, tell him "go potty", reinforce it & reward him when he does. Keep water away from him in the evening & limit it during the day. Are you using a crate? If not, I would recomend it, not as a punishement, but as a place where Rossi can go to get away, also I would try having him sleep in there...
There's a lot more & I'm sure someone else will fill in the blanks that I forgot, but that's a start....Keep us posted & feel free to ask away if you have any problems