One of the five Marines killed in a California helicopter crash last week was a decorated soldier from Dover.

Capt. Jack Casey was one of the pilots of the CH-53E Super Stallion helicopter that went down in the mountains outside San Diego during a historic storm.

“Capt. Jack Casey gave his life while serving his country," Governor Chris Sununu said in a statement. “Valerie and I are deeply saddened as we mourn the loss of these five Marines. Capt. Jack Casey’s death is a profound loss for his family, his community, New Hampshire, and the country.”

Sununu directed all flags at public buildings and grounds to fly at half-staff on the day of interment.”

Casey was commissioned in the Marine Corps on May 16, 2019, and earned the rank of Captain on September 1, 2023. His decorations include the National Defense Service Medal, according to the U.S. Marine Corps.

The Marine Corps released the names Friday of the five Marines killed. All of them were in their 20s.

The decorated Marines were assigned to Marine Heavy Helicopter Squadron 361, Marine Aircraft Group 16, 3rd Marine Aircraft Wing and were based at Marine Corps Air Station Miramar in San Diego.

“We have been confronted with a tragedy that is every service family’s worst fear,” said Lt. Col. Nicholas J. Harvey, commanding officer of the squadron. “The Flying Tigers family stands strong and includes the friends and community who have supported our squadron during this challenging time. We will get through this together.”

The youngest was Lance Cpl. Donovan Davis, 21, of Olathe, Kansas, who was just promoted to the rank of lance corporal on New Year’s Day. The oldest was Capt. Miguel Nava, 28, of Traverse City, Michigan.

Davis and Sgt. Alec Langen, 23, of Chandler, Arizona, were both crew chiefs. The rest were CH-53E pilots.

“We will miss him dearly,” his mother Caryn Langen told KNSD-TV of San Diego.

The other pilot on board was Capt. Benjamin Moulton, 27, of Emmett, Idaho.

The Super Stallion vanished late Tuesday night on its way back to Miramar from Creech Air Force Base. The craft was discovered Wednesday morning near the mountain community of Pine Valley.

The military confirmed Thursday that all five Marines were killed when their helicopter went down during stormy weather, and efforts were underway to recover their remains, which will take weeks because of the rough terrain and weather, said Col. James C. Ford, operations officer with 3rd Marine Aircraft Wing. In the meantime, Marines are staying with the remains round-the-clock to adhere to their ethos of never leaving any Marine behind.

The military is investigating the crash.