Officials with the Washington-based investigative non-profit are pressing for credible probe of allegations that Chicago mass transit officials misled the federal government in order to get more tax dollars from Washington.

"We are continuing to investigate the web of facts that are beginning to emerge about when the Federal Transit Authority knew about this misreporting, and why there has yet to be any serious investigation," said Dan Epstein, executive director of Cause of Action.

"We will continue to use the Freedom of Information Act to bring transparency to how taxpayer dollars are being used, or in this case, misused, by the FTA and the Chicago Transit Authority," he said.

Earlier this week, it was learned that in April FTA Administrator Peter Rogoff ordered the Chicago officials to revise their count of mileage covered by CTA vehicles, and to change the way it counts miles that are used in a formula for allocation federal transit program funding.

But Rogoff said in a statement released yesterday that "FTA has no indication that the CTA used any of the formula funds for anything other than eligible purposes to provide needed transit services to the public."

Epstein's vow to continue digging follows his organization's release last week of a report in which it revealed a 2007 audit by Illinois state officials claimed CTA had received as much as $5 million more than it should have. The FTA said the overpayments were closer to $800,000 annually.

The Cause of Action report suggested that the FTA didn't conduct a credible investigation of the situation because Robert Rivkin, who is general counsel of the U.S. Department of Transportation had previously been general counsel at CTA between 2001 and 2004. The report also pointed out that Valerie Jarriett, considered by many to be President Obama's closest advisor in the White House, had served as chairman of the CTA board between 1995 and 2003.

Federal and Chicago transit officials denied involvement in a mileage mis-counting scheme by Rivkin or Jarrett, saying the tabulation and reporting process is routinely handled by other employees.

But Epstein contends the mis-counting could have been in place as far back as 1982 and he called for investigations by FTA's Inspector-General and by the Justice Department.

"If each year'sexcess was at least $1 million and up to $5 million, the CTA could potentially have fraudulently claimed and received $30 million to $150 million in taxpayer funds," Cause of Action said in its report.

Go here to read the full Cause of Action report.