Securities regulators say a Long Island stockbroker was already under investigation for alleged professional misconduct when he was charged criminally with sinking the Broadway musical “Rebecca” with a bizarre fraud.

The Financial Industry Regulatory Authority began investigating Mark Hotton in 2009 after a customer complaint, according to the Wall Street Journal.

The authority says it was among 12 complaints and arbitration cases against Hotton before his arrest last Monday on money-laundering and fraud charges in connection with the “Rebecca” case.

Prosecutors say he flimflammed the musical’s producers with an elaborate scheme.

Authority spokesman Nancy Condon said the investigation into his profession conduct was ongoing. It was expected to be wrapped up soon.

Hotton’s attorney declined to comment on the investigation. He said Hotton didn’t set out to defraud the show.