A lawyer for a Reserve Marine being forced out of the Marine Corps for mishandling classified information vowed to appeal the Department of the Navy's Navy Department's decision to uphold the involuntary discharge, calling it "obvious retaliation."

A lawyer for a Marine being forced out of the Corps vowed to appeal as "obvious retaliation" a Department of the Navy decision upholding the involuntary discharge of the officer for mishandling classified information in an attempt to warn others in the war zone about a suspected Taliban conspirator.

In a case that gained widespread notoriety, Maj. Jason Brezler, a civil affairs officer who had returned stateside, shared classified information with colleagues in Afghanistan in 2012 in an attempt to warn them about a suspected Taliban conspirator. Brezler's fears proved well-founded two weeks later when an insider attack in Helmand province claimed the lives of three Marines.

Michael Bowe, the lawyer representing Maj. Jason Brezler, a Reserve civil affairs officer, told Marine Corps Times they learned via email Monday of the decision to uphold the separation. The decision, first reported by The Washington Post, was made by Scott Lutterloh, the acting assistant Navy secretary for Mmanpower and Rreserve aAffairs. Made official on Nov. 24, the decision comes more than three years after Brezler was investigated for sending a classified document from a personal email account.

Bowe said they will continue arguing Brezler's case in a civilian federal court. He contends that senior Marine commanders retaliated against his client after Brezler sought the support of his congressman, Rep. Peter King, R-N.Y. The lawsuit states that Brezler was sent to a 2013 board of inquiry in retaliation for his protected communications with King, and that the proceeding failed to comply with due process.

"He was talking to his congressman about embarrassing misconduct the Marine Corps did not want anyone discussing," Bowe said. "That obvious retaliation is illegal and we are confident the federal court will overturn this action on that and other equally compelling grounds."

The U.S. District Court for the Eastern District of New York will now consider their challenges to Brezler's separation, Bowe added. A Marine spokesman said it's not immediately clear how the pending federal lawsuit will affect Brezler's discharge.

Despite having had backing from members of Congress and top military leaders during his December 2013 board of inquiry, Brezler was found to have mishandled classified information. It was recommended that Brezler, a New York City firefighter, be honorably discharged from the Corps.

The email Brezler sent that prompted the investigation was meant to alert Marines in Afghanistan about Sarwar Jan, a corrupt Afghan police chief believed to have ties to the Taliban. About two weeks later, the three Marines were killed when one of Jan's "teaboys" — a personal servant — gunned them down on a Marine outpost. Killed in the attack were Staff Sgt. Scott Dickinson, 29, Cpl. Richard Rivera, 20, and Lance Cpl. Greg Buckley, 21.

The attacker was sentenced to about seven years in an Afghan prison, which is the maximum sentence for a minor there.

The Buckley family, unsatisfied with the information provided by the Marine Corps leading up to that trial, filed their own lawsuit in the Eastern District Court of New York. Bowe said the court denied the government's motion to dismiss that case last month. They're expected to begin the pre-trial discovery process soon, he added.