'Below Deck' Star Captain Lee Says Bankruptcy Case is a Fraud, Feds Investigating

Captain Lee Rosbach claims someone filed for bankruptcy for him without his knowledge or consent and he has no idea why ... but he's on the hunt and is looking for revenge.

The "Below Deck" sea captain tells TMZ ... he was shocked to hear reports of his bankruptcy case while he was out at sea filming for season 5.

Lee notified the Dept. of Justice which launched a federal investigation, targeting 2 individuals whose names also appear on the bankruptcy docs -- Maurice Clarence Jeffries and Edward Tinsley. Lee says he doesn't know either. The feds seem to be buying Lee's story.

The "Below Deck" Captain says he has hard proof it's all BS ... the signature on the bankruptcy petition is forged and the social security number is wrong.