The most they could reasonably do here is attempt to sue for fraud for lost time and salary paid. It's unlikely that they can bring a criminal fraud case, so they have to prove damages.

Damages in this case are probably

- Lost time interviewing

- Any salary paid

If they caught this on day 1, they just don't have enough damages to make this worth pursuing (aka - they lose far more money trying to actually bring a case than they would be just firing him immediately and eating the lost time).

Basically - why waste time on a small claims verdict against this guy for trivial amounts of money?

The courts aren't going to lock him up for this, and even if they win, he can still go right to the next company and try again.

This is the kind of thing that other professions attempt to solve with extra-legal associations and certifications (ex: a lawyer might be disbarred for this - an action taken by the bar association that revokes his attorney's license, making it impossible for him to practice in areas that require such a license).

But software really has no such guardrails in current society (both a blessing and a curse).

I don't really know what it is you'd prefer this company have done in this case.