[dragonwriter]

You should look into federal and state labor authorities; while a lawyer not being paid upfront (one who would be taking a contingency fee) may balk at a case without more up-front evidence, public authorities may be willing to open an investigation with just a basic colorable claim. There will still need to evidence that you were fired for using paternity leave, but you may not bear the burden of uncovering it.

[EggsOnToast]

I've seen this idea play out in a differen't industry and if your claim resembles something legitimate then it has promise. The only reason I say legitimate is because in the version I was privy to it was a disgruntled employee lying through her teeth about almost cartoonishly evil happenings. She was threatened with criminal prosecution for intentionally, key word there, trying to deceive the investigator.