Can a person get deported from the US for working outside visa 5 years ago?

Both your girlfriend and her employer are guilty of wrongdoing. When she realized the job was not legit, she should have returned home to Japan. Surely she had friends or family who could have lent her money or if really desperate, she could have sought help from her embassy. Instead, she chose to work illegally for cash, and the math doesn't quite add up. First, her visa was obtained four years ago and was good for only two years. Did she overstay that visa and thus has been living here illegally for the last two years? I also wonder how she managed to get by for two years on just $2,000 and a few months of working at minimum wage. If what you say is true, that he hired only her and no other employees, then yes, it will look like immigration fraud to USCIS, and he will be in trouble, too. If she has not been served with a notice to appear yet, then it is not too late for you to marry and file for a green card. Paying for a consultation with a Alia lawyer prior to getting married would be a wise investment.