Search for 12 Missing Marines Suspended, Coast Guard Says Today marks the fifth day searching for the 12 missing crew members

 -- The search for 12 missing Marines -- whose helicopters went down off the Hawaiian coast -- was suspended Tuesday after five days of searching, the Coast Guard said.

The decision to suspend the search at sunset local time came after four life rafts were found in the desperate search for the service members off Oahu.

A U.S. Navy salvage ship -- equipped with sonar and a remotely operated vehicle -- had joined the underwater search effort near the last known position of the two CH-53E Super Stallion helicopters.

The Coast Guard earlier said that by sunset Tuesday, rescuers would have searched more than 40,000 nautical square miles.

"A decision to suspend searching without finding survivors is extremely difficult given the depth of its impact and I know I speak for the entire Coast Guard when I say our thoughts and prayers are with Marine Corps helicopter squadron and particularly with families and loved ones of those missing,” said Capt. Jim Jenkins, of the Coast Guard.

According to Marines spokesman Captain Timothy Irish, 400-500 service members had been still actively searching in treacherous conditions below water, above water, and along the shoreline for any clues that could lead them to the missing crew.

"Our focus is to locate these Marines and know with absolute certainty we've thoroughly canvassed every location we might find them,” Coast Guard spokesman Lt. Scott Carr said yesterday during a press briefing.

The Coast Guard was first notified of the missing helicopters late Thursday night when a civilian called about a fireball in the sky. Another report also spoke of a flare in the sky, according to Lt. Carr, but it remains unclear if the fireball and flare are related.

Over the weekend the 12 missing Marines were identified as Maj. Shawn M. Campbell, 41, College Station, Texas. Capt. Brian T. Kennedy, 31, Philadelphia, Pennsylvania. Capt. Kevin T. Roche, 30, St. Louis, Missouri. Capt. Steven R. Torbert, 29, Florence, Alabama. Sgt. Dillon J. Semolina, 24, Chaska, Minnesota. Sgt. Adam C. Schoeller, 25, Gardners, Pennsylvania. Sgt. Jeffrey A. Sempler, 22, Woodruff, South Carolina. Sgt. William J. Turner, 25, Florala, Alabama. Cpl. Matthew R. Drown, 23, Spring, Texas. Cpl. Thomas J. Jardas, 22, Fort Myers, Florida. Cpl. Christopher J. Orlando, 23, Hingham, Massachusetts. Lance Cpl. Ty L. Hart, 21, Aumsville, Oregon. A memorial is being planned for Friday.

The cause of this accident is still under investigation by the Marine Corps. According to Gen. Russell Sanborn, the Marines will now take responsibility for a recovery and salvage operation.

Erin Dooley contributed to the reporting of this story.