A document obtained by ABC News indicates allegations of threatening behavior and sexual harassment toward a female staff member by Mahoney go beyond his public confession, including claims that he urged one of his mistresses to "tease" donors.

Mahoney last week confirmed he hired a mistress for his congressional staff and he had an affair with a Florida county official who sought his help with a federal grant. The former congressional staff member was paid $121,000 by Mahoney after she was fired and threatened to sue.

Both current and former employees told ABC News allegations against Mahoney in a "demand letter" sent to the lawmaker by the fired staff member's attorneys were supported by taped phone conversations between Mahoney and Allen.

The U.S. House of Representatives ethics committee is investigating Mahoney's conduct.