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Grace Wyler

Amid brewing controversy over the ATF's botched Fast and Furious gunrunning operation comes new allegations that the Department of Justice also let off an Arizona man suspected of supplying grenades to Mexico's drug cartels.

The WSJ reports today that federal authorities are now investigating why the U.S. Attorney's office in Phoenix — the same office that oversaw Fast and Furious — released Jean Baptiste Kingery after he confessed to providing military-style weapons to the now-defunct La Familia Michoacana drug cartel.

Kingery, who was arrested and released in June 2010, confessed to manufacturing improvised explosive devices (IEDs) using grenade components from the U.S. He also admitted to helping the cartel convert semi-automatic rifles into machine guns. Mexican criminal organizations are increasingly using these military-style weapons as the cartels' escalate their wars against the government and one another.

Despite Kingery's confession, and over loud protestations from the arresting ATF officers, the U.S. Attorney's office let Kingery go within hours of his arrest.

Kingery's release is now the subject of an internal probe by the DOJ inspector general. The findings in the DOJ probe were a major catalyst in the recent staff shakeup that ousted Arizona U.S. Attorney Dennie Burke and Acting ATF Director Kenneth Melson from their posts.

The Phoenix U.S. Attorney's office denies that it declined to prosecute the case, saying that it wanted to continue surveillance. The office alternatively told investigators that ATF agents wanted to make Kingery an informant, but lost contact with him within weeks of his release.

Prosecutors involved in the case also accuse ATF agents of devising a failed sting that allowed Kingery to take hundreds of grenade parts across the border in the months about six months prior to his arrest.

The Congressional Oversight Committee has also expanded its Fast and Furious investigation to include the Kingery case. The Committee is investigating who in the Obama administration knew about the gunrunning program, under which ATF agents allowed more than 2,000 guns to "walk" across the border.

The Fast and the Furious case has escalated over the past weeks, with news that at least three White House national security officials knew about the gunrunning program.

Emails obtained by the Committee last week show contact between the head of the Phoenix ATF and Kevin O'Reilly, then-director of North American affairs, about the operation. The White House confirmed that O'Reilly briefed Dan Restrepo, senior director for the Western Hemisphere, and Greg Gatjanis, director of counterterrorism and narcotics.

The emails, first reported by the LA Times, do not indicate that the White House aides knew about the more controversial tactics of letting the guns "walk." There is also no indication that the information went beyond those three officials.

Now here's everything you need to know about the Fast and Furious scandal >

Did The ATF Try To Cover Up Ties To The Murder Of A U.S. Border Patrol Agent?

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