Bad theory. Because:
There's only two Mafia left. Which would mean German and I would both be showing up in suspect lists constantly. Now that German is dead, if I were Mafia, I would show up in every single suspect list after this. People would catch on when I showed up twice, and fry me. Game over. That's why, if I were Mafia, I would be trying to save German to make me not look as bad in the future.
Hmm, I wonder who defended German earlier. He would be doing that, just like I said, to take the heat off himself later on.