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.