Four former Blackwater security guards who were found guilty in a deadly Baghdad shooting have appealed their convictions on Monday.

The men argued that a key witness against them had changed his testimony after the trial and that prosecutors lacked jurisdiction to even bring the case.

The appeals, long expected, represent the latest legal volley in a criminal case that’s spanned years in Washington’s federal court and that concluded with guilty verdicts following a months-long trial in 2014.

Nicholas Slatten, 32, ¬†who is serving a life sentence on a charge of first-degree murder, filed a separate brief saying the prosecution against him was ‘vindictive’ and that the jury didn’t have sufficient evidence for a murder conviction.

Three other former guards, Paul Slough, Evan Liberty and Dustin Herd, were found guilty of manslaughter and firearms charges carrying mandatory 30-year sentences.

Slatten’s appeal raises multiple legal arguments, including that the jury didn’t have enough evidence to find him guilty of murder.

The case arose from the Nisour shooting in 2007 that that prosecutors say left 14 civilians dead at the crowded traffic circle in downtown Baghdad.

The shooting strained international relations and drew scrutiny to the role of American contractors in war-torn Iraq.

Amid an international outcry the FBI launched a criminal probe into what soon become known as ‘Baghdad’s Bloody Sunday’.

Slatten was accused of firing the first shots and convicted of first-degree murder.

The two sides presented the jury with radically different accounts of the events: Prosecutors described the killings as a one-sided ambush of unarmed civilians, while defense lawyers said the guards opened fire only after a white Kia sedan seen as a potential car bomb threat began moving quickly toward their convoy.

Central to the appeal is a witness who defense lawyers say changed his account of what happened in a way that undermines the government’s narrative.

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