Note: This story has been updated since it was first published.

A drill sergeant at the Army’s largest basic training post was sentenced to 18 months in prison Tuesday, the day after he plead guilty to three counts in connection with an October 2017 accident in which he fell asleep and drove into a group of trainees on a road march.

Staff Sgt. Andrew Marrow admitted fault to two counts of negligent homicide and one count of dereliction of duty, Fort Jackson, South Carolina, spokesman Michael Pond confirmed to Army Times on Tuesday.

“Today was a hard, somber day, but a necessary day,” Brig. Gen. Milford Beagle Jr., Fort Jackson’s commander, said in a release. “My hope is that today will bring closure to the families and friends of Pvts. Ethan Shrader and Timothy Ashcraft, those who were injured in this tragic incident, and those affected by it; including the Fort Jackson community.”

Marrow nodded off while driving a Ram pickup towing a water trailer behind a ruck march. Six soldiers were injured and two ― Pvts. Ethan Shrader and Timothy Ashcraft ― were crushed to death when the trailer rolled over them.

“I awake to numerous people screaming and shouting,” Marrow said Monday in a prepared statement before the court on Monday, according to the Post and Courier.

Ashcraft’s mother testified at the trial, as did a former trainee who suffered a broken spine and laceration to her liver, the Post and Courier reported.

“I am a parent, too, and I have no ability to understand the pain that I have caused you,” Marrow said Tuesday before sentencing, addressing the victims’ families, the Post and Courier reported, adding, “I can never replace what you have lost or what I have taken.”

Marrow was taken to the Naval Consolidated Brig Charleston, South Carolina, following the hearing, according to the release. His sentence includes a reduction to E-1 and forfeiture of pay, but as the sentence is over one year, the case will automatically be heard by the Army Court of Appeals.

“It is my sincere hope that the healing process can begin,” Beagle said. “The Army family has always taken care of each other in times of need, and I’m confident that will happen in this case.”