Updated

Nearly two-dozen senators issued a bipartisan call for the Justice Department to lead a criminal probe into the Veterans Affairs scandal, citing mounting evidence of secret waiting lists and other "potential criminal wrongdoing."

The letter to Attorney General Eric Holder came as the department released an internal review showing more than 57,000 veterans have been waiting for up to three months for medical appointments. An additional 64,000 who enrolled for VA health care over the past decade have never been seen by a doctor, according to the audit.

The department, as well as the VA inspector general, are reviewing the problems in the sprawling veterans health care system. The Justice Department is being consulted -- but Sens. Richard Blumenthal, D-Conn., John McCain, R-Ariz., and others want the DOJ to take a "leadership role" in the probe.

"Evidence of secret waiting times, falsification of records, destruction of documents, and other potential criminal wrongdoing has appalled and angered the nation, and imperiled trust and confidence in the Veterans Health Administration," 21 senators wrote in a letter sent late last week to Holder.

"The spreading and growing scale of apparent criminal wrongdoing is fast outpacing the criminal investigative resources of the IG, and the revelations in the interim report only highlight the urgency of involvement by the Department of Justice," they wrote. "This challenge requires resources that only the Department of Justice can provide in developing and assessing evidence, pursuing leads, and initiating active prosecutions aggressively if warranted."

The senators cited a May 28 interim report from Veterans Affairs Inspector General Richard Griffin.

At a hearing by the House Veterans Affairs Committee Monday night, Griffin said, "Once someone loses their job or gets criminally charged, it will no longer be a game. And that will be the shot heard around he system."

The internal audit released Monday outlined additional problems. The audit said a 14-day target for waiting times was "not attainable," given growing demand for VA services and poor planning. It called the 2011 decision by senior VA officials setting it, and then basing bonuses on meeting the target "an organizational leadership failure."

The audit released Monday said 13 percent of VA schedulers reported getting instructions from supervisors or others to falsify appointment dates in order to meet on-time performance goals. About 8 percent of schedulers said they used alternatives to an official electronic waiting list, often under pressure to make waiting times appear more favorable.

Acting VA Secretary Sloan Gibson said the audit showed "systemic problems" that demand immediate action. VA officials have contacted 50,000 veterans across the country to get them off waiting lists and into clinics, Gibson said, and are in the process of contacting an additional 40,000 veterans.

The audit is the third in a series of reports in the past month into long wait times and falsified records at VA facilities nationwide. The controversy forced VA Secretary Eric Shinseki to resign May 30. Shinseki took the blame for what he decried as a "lack of integrity" in the sprawling system providing health care to the nation's military veterans.

The Associated Press contributed to this report.