WASHINGTON — The Army general who has led war crimes prosecutions at Guantánamo Bay, Cuba, for a decade is retiring and handing off the trial of the five men accused of conspiring in the attacks of Sept. 11, 2001 to an as-yet unchosen successor.
Brig. Gen. Mark S. Martins of the Army served as chief prosecutor for military commissions throughout the Obama and Trump administrations.
His decision to retire came as a surprise because he had obtained an extension to serve in the post until Jan. 1, 2023. Instead, he will retire on Sept. 30, according to a notice sent by Karen V. Loftus, a prosecution staff member, to families of the 3,000 people killed in the Sept. 11 attacks.
Defense officials said a board was likely to be assembled to select a new chief prosecutor, who will be of the rank of Army colonel or Navy captain rather than the rank of a one-star general.
General Martins, a Harvard Law School-educated West Point graduate, had for many years been the public face of military commissions. In his first years in the position, he undertook a speaking campaign to promote the hybrid form of justice that the Bush administration established after the invasion of Afghanistan.
The Obama administration made some changes to the system and pursued the Sept. 11 case against Khalid Shaikh Mohammed and four accused accomplices at Guantánamo, rather than in federal court. Their case has been mired in pretrial proceedings since arraignment in May 2011.
Although the case currently has no military judge assigned to hear it, Pentagon officials are preparing for its first hearings since February 2020 to take place in the first two weeks of September, coinciding with the 20th anniversary of the attacks.
Ms. Loftus said General Martins chose to retire “in the best interests of the ongoing cases.” Military Commissions hearings are scheduled to resume next week for the first time since the beginning of the pandemic, in a case accusing an Iraqi man of commanding forces that committed war crimes in Afghanistan in 2002 and 2003.
Ms. Loftus called the timing “an ideal window to identify a successor” because proceedings are “finally in view again for all of our cases following the pandemic-driven hiatus.”