After five days of 24-hour searching, the Coast Guard announced that it was calling off the search for the 12 Marines who went missing after a a helicopter crash on the Pacific Ocean. In an official statement, the service expressed its regret that it could not locate any survivors.

“The decision to suspect the search without finding survivors is particularly difficult,” Capt. Jim Jenkins, chief of staff and acting commander for the Coast Guard’s 14th District, said. “We will continue to provide any comfort we can from this terrible loss.”

The search will officially end at 11 p.m. EST on Wednesday, or sunset in Hawaii.

It’s still unclear why the two Ch-53E Super Stallion helicopters collided nearby the coast of Oahu, Hawaii. Each aircraft was carrying six Marines, and all 12 passengers have been missing ever since the initial helicopter crash.

The beginning days of the search were also hampered by choppy waves and stormy weather, including winds as fast as 23 mph and waves tall as 30 ft. A laser pointer also forced search parties to change course in order to keep rescue crews safe.

A memorial service for the helicopter crash victims will be held at Marine Corps Base Hawaii on Friday. The service will honor the following lost Marines:

Maj. Shawn M. Campbell
Cpl. Matthew R. Drown
Lance Cpl. Ty L. Hart
Cpl. Thomas J. Jardas
Capt. Brian T. Kennedy
Cpl. Christopher J. Orlando
Capt. Kevin T. Roche
Sgt. Adam C. Schoeller
Sgt. Dillon J. Semolina
Sgt. Jeffrey A. Sempler
Capt. Steven R. Torbert
Sgt. William J. Turner

UPDATE:

After calling off the search, the Marine Corps has officially declared the 12 helicopter crash victims deceased. According to Military.com, some human remains were discovered in the helicopter wreckage.

“Our thoughts and prayers are with the Marines and their families as we all mourn this tragic loss of life,” the Marine Corps said in a statement.