First, I would find out from the girlfriend if she let it loose or if she simply gave it away/sold it. Letting it loose in the wild is not only illegal, but also animal cruelty in my book.
Also, tell your friend that while he is living with his girlfriend, he needs to not have reptiles. Bringing reptiles into a home where one person is clearly uneasy about it and only gives in because she was badgered or she only wanted to make the other person happy is not a good mix. Things like this happen and it is the animal that suffers. If she comes around and starts to like reptiles, that's great and he can get another. But if stuff like this is going to happen, it is in the best interest of everyone if he didn't get reptiles.