The 2012 GOP presidential nominee is suggesting the real reason Trump is not releasing his tax returns is that the billionaire is hiding “a bombshell of unusual size” in the documents.

The accusation came in a pointed Facebook post Wednesday as likely Democratic presidential candidate Hillary Clinton slammed Trump over the transparency issue.

Trump said in an AP interview Tuesday that he doesn’t believe he has an obligation to release his tax returns and won’t release them before November — unless an ongoing audit of his finances is completed before Election Day. He said he wouldn’t overrule his lawyers and instruct them to release his returns if the audit hasn’t concluded by then.

Romney called any refusal by Trump to release his tax returns before Election Day, “disqualifying.”

It has become tradition over the last three decades for presidential nominees in both parties to release their returns.