A soldier shoots a SIG Sauer M17 pistol during weapons qualification training at Joint Base McGuire-Dix-Lakehurst, N.J., on June 3, 2026. An M17 pistol was involved in the March shooting death of Pfc. Krystofer Lopez during firearms training at Letterkenny Army Depot in Pennsylvania. (Seth Cohen/U.S. Army)
A former civilian firearms instructor at an Army base in Pennsylvania who fatally shot a reservist soldier during training earlier this year will plead guilty to involuntary manslaughter, according to court documents released this week.
Sean Stark, 38, was charged in the death of Spc. Krystofer Lopez, 18, at Letterkenny Army Depot on March 12, the Justice Department said Monday.
Prosecutors simultaneously filed an agreement with Stark to waive his right to indictment by a grand jury and plead guilty to the felony charge.
Stark acknowledged in the agreement that his conduct leading to Lopez’s death was “grossly negligent” and carried out “with reckless disregard for human life,” according to documents filed Monday in federal court in Harrisburg.
The Army Criminal Investigation Division did not immediately respond to a request for an incident report or other information regarding its investigation into Lopez’s death.
Lopez was posthumously promoted to the rank of specialist, according to a March 16 Congressional Record release.
Stark was previously identified as a Directorate of Emergency Services law enforcement officer and Security Division firearms and active-shooter instructor at Letterkenny Army Depot.
On the day of the shooting, he was leading a group of Army reservists, including Lopez, through firearms training, prosecutors said.
He stepped outside the shoot house for a cigarette break and inserted a loaded magazine into his M17 pistol before returning with the weapon, local NBC affiliate WGAL reported Monday, citing information provided by Lopez’s parents.
After returning, Stark pointed the loaded weapon at Lopez, instructing him to point his own weapon at Stark as part of the exercise.
Stark’s pistol then discharged, with the bullet hitting Lopez in the chest in an area not covered by his protective vest, WGAL reported in July.
According to the Lopez family, the shooting was captured on video, which was turned over to investigators. Lopez was transferred to a local hospital, where he was pronounced dead, they added.
The criminal complaint says Stark was carrying out a lawful act “without due caution and circumspection.”
Stark’s plea hearing has not yet been scheduled, the Justice Department said. If convicted, he faces a maximum sentence of eight years in prison, according to the plea deal summary.
“The circumstances surrounding Mr. Lopez’s death are heartbreaking for his family and loved ones,” U.S. Attorney Bryan Miller said in the statement. “I hope this prosecution brings some relief for the family while ensuring that justice is delivered.”
In an emailed statement, Edward Paskey, Stark’s lawyer, told Stars and Stripes that his client and his family express their “deepest condolences” to the family of Lopez.
The circumstances surrounding Specialist Lopez’s unintentional death are tragic,” Paskey said. He added that “out of respect for Specialist Lopez and his family, neither Mr. Stark, nor counsel will be making additional public statements in the immediate future.”
