Democrat Scott Harshbarger will conduct the internal investigation.
ACORN said last week that it was suspending the admission of new clients into its housing program pending the outcome of its investigation and had fired several employees. It has said it will do whatever necessary to restore public trust.
Video shot by the couple in Brooklyn appears to show ACORN employees advising the pair to lie about the source of their income or to launder the money to get housing assistance. The Brooklyn video and footage shot by the couple in other cities has been running on the Internet and television news programs for days.
Republicans, who previously accused ACORN of voter registration fraud, are calling for federal and state investigations into the group. The inspectors general for the Department of Housing and Urban Development and the Justice Department have confirmed they are investigating their agencies' involvement with the group.
Even Democrats usually friendly to the Democratic-leaning organization have called the actions of the employees in the videos inexcusable, and the Democratic-controlled Congress is moving to cut off federal funding for the group.
ACORN has condemned the actions of the two employees who appeared in the Brooklyn footage, but also contends parts of the video shot there and elsewhere by the hidden-camera couple were manipulated.
Harshbarger was Massachusetts attorney general in the 1990s. He later ran unsuccessfully for governor before becoming head of the government watchdog group Common Cause, where he pushed for tougher campaign finance laws.
Harshbarger currently is an attorney in Boston with the law firm Proskauer Rose LLP, where his specialties include corporate governance and corporate defense and investigations.
ACORN is short for the Association of Community Organizations for Reform Now.
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Meanwhile in California, police say a worker with the activist group ACORN who was caught on video giving advice about human smuggling to a couple posing as a pimp and a prostitute had reported the incident to authorities.
National City police said Monday that Juan Carlos Vera contacted his cousin, a police detective, to get advice on what to with information on possible human smuggling.
Vera was secretly filmed on Aug. 18 as part of a young couple's high-profile expose.
Police say he contacted law enforcement two days later. The detective consulted another police official who served on a federal human smuggling task force, who said he needed more details.
The ACORN employee responded several days later and explained that the information he received was not true and he had been duped.
Vera was fired on Thursday.