Commandant Gen. James Amos, shown here in 2011, has faced tough scrutiny as a result of an inspector general complaint filed by Maj. James Weirick, a staff judge advocate who worked at Quantico, Va. The IG has found that the general did not illegally manipulate the legal cases of Marines who were court-martialed for urinating on Taliban remains in Afghanistan and recording video of it. (U.S. Navy photo by Mass Communication Specialist 2nd Class Kevin S. O’Brien)

The last piece of a 16-month investigation against the Marine Corps’ top officer, Commandant Gen. James F. Amos, has come to close with the general cleared of wrongdoing.

The Defense Department Inspector General did not substantiate allegations that Amos  inserted himself illegally into the military justice system to ensure tough punishments against Marine scout snipers who were depicted in a video urinating on dead Taliban fighters in Afghanistan, a Pentagon official told The Washington Post on Monday. The news was first reported by Marine Corps Times over the weekend, citing an anonymous Defense Department official. The investigation is said to have ended July 24.

The case began when Maj. James Weirick, a Marine attorney then serving at Quantico, Va., filed a complaint with the Pentagon IG in March 2013 alleging that the cases against the snipers was tainted because Amos and other members of his staff had inappropriately got involved. Weirick focused on the commandant’s decision to remove the three-star general assigned to oversee the cases, Lt. Gen. Thomas Waldhauser, after learning that he intended to impose administrative nonjudicial punishment on some of the Marines, rather than move forward with a court-martial. Doing so, Weirick argued, amounted to unlawful command influence, in which a senior officer seeks to pressure a junior commander for a certain outcome in a case.

Waldhauser said in a sworn statement in July 2013 for one of the cases that Amos told him he wanted the Marines “crushed,” and stripped Waldhauser of his control over the cases shortly after disagreeing with how the three-star general was handling them. Waldhauser acknowledging that was highly unusual — active-duty generals rarely speak out against their service chief.

The commandant had denied Waldhauser’s version of events in an interview with NPR in February, effectively pitting a three-star general’s comments, against a four-star’s.

Some critics of the commandant’s are have called for him to release the IG investigation report. Retired Marine staff judge advocate Lee Thweatt, for example, called for Amos to release the results in an essay on the website on Sunday, saying doing so would explain how the IG’s office came its “astonishing conclusions.”

The law does not require that. It is standing policy for the IG to release the results of investigations that substantiate misconduct. When an investigation does not, however, they are typically withheld due to privacy concerns.

Indeed, Marine Corps officials declined to confirm Monday the conclusion of the investigation, releasing only a one-sentence statement when asked if Amos’ office would release the results of the investigation.

“We do not have the necessary release authority to provide details, or confirmation of status, associated with the subject of your query on behalf of the Marine Corps or our Commandant,” said the statement, released by Maj. John Caldwell, a Marine Corps spokesman.