Issa cries foul after key player in Fast and Furious scandal refuses to testify

As Arizona state officials open their own probe into Operation Fast and Furious, the head of the House panel investigating the gunrunning scandal is crying foul over a key player's move Tuesday to assert his Fifth Amendment right to refuse to answer questions.

Patrick Cunningham, the chief of the criminal division of the U.S. attorney's office in Arizona, was excused from a deposition after refusing to give more than his name and title, Fox News has learned.

Cunningham informed the House Oversight and Government Reform Committee through his attorney that he would use the Fifth Amendment protection after being subpoenaed last week to testify in front of congressional investigators regarding his role in the operation that sent more than 2,000 guns to the Sinaloa drug cartel. Guns from the failed operation were found at the murder scene of Border Patrol Agent Brian Terry in 2010.

Committee Chairman Darrell Issa called the decision a "startling development" and in a letter to Attorney General Eric Holder wrote that the refusal to testify implies that "Mr. Cunningham may have engaged in criminal conduct with respect to Fast and Furious is a major escalation of the department's culpability."

Issa said Justice Department officials claim Cunningham misinformed them about Fast and Furious as the department prepared its initial response to Congress' inquiry into the failed program. Cunningham's lawyer denies those allegations.

Cunningham was excused from the deposition, but may be called again later, according to the letter. The committee may also issue additional requests or subpoenas for Cunningham's associates in the U.S. Attorney's office.

The Justice Department declined to comment. The committee's ranking Democrat, Rep. Elijah Cummings of Maryland, said that while he is "disappointed" Cunningham would not testify before the committee, "I respect his constitutional rights. It is inappropriate for Chairman Issa to engage in wild and unsubstantiated speculation about why he did so."

Holder is expected to be questioned about this when he testifies in front of the panel next Thursday.

On Monday, two men, Jacob Wayne Chambers and Jacob Anthony Montelongo, each pleaded guilty in federal court to a conspiracy charge tied to the scandal. Montelongo also pleaded guilty to dealing guns without a license.

The pair admitted being part of a 20-person smuggling ring that is accused of running guns into Mexico for use by the Sinaloa cartel.

Two rifles bought by the ring were found at the scene of a December 2010 shoot-out near the Arizona-Mexico border that mortally wounded Terry. The two guns weren't purchased by Chambers and Montelongo but were bought by another alleged ring member.

Meanwhile, back in Arizona, lawmakers are beginning their own probe into Operation Fast and Furious.

A special committee was formed to find out if state gun dealers were coerced by federal officials into selling guns to buyers they knew were criminals.

"I know one thing, some of them will testify they were forced to do it under the threat of losing their license to sell firearms in this state. That's wrong and we're gonna investigate it," said Republic state Rep. David Burnell Smith.

State officials will also look into victims injured by Fast and Furious weapons. As of now, only two incidents tied to the guns are known about in the United States -- the murder of Terry and a non-fatal shooting of a state police officer.

State laws broken by federal officials could include misconduct involving weapons, conspiracy or aiding and abetting those involved in a crime.

"We have waited long enough," said Arizona House Speaker Andy Tobin. " This thing is over a year old. It is time to move forward and see where we are going to be, to see what really happened."

The bipartisan committee's report is due March 1. Use of a grand jury, the state attorney general or a special prosecutor to issue subpoenas will be decided this week.