The El Faro, a U.S.-flagged cargo ship that was reported missing as Hurricane Joaquin swept through the western Atlantic, sunk near the Bahamas, the U.S. Coast Guard said Monday. A body, debris and two empty lifeboats were spotted by helicopters in the area of water where the ship last transmitted its coordinates. No signs of life there have been reported. 

“For our search planning efforts, we are assuming that the vessel has sunk,” U.S. Coast Guard Capt. Mark Fedor told the Associated Press. “We are searching for any signs of life for that vessel.”

The 790-foot container ship had a 33-member crew, of which 28 are American and five Polish. The ship was last seen between the Bahamas' Cat Island and San Salvador Island, which both lie inside the Bermuda Triangle.

Its last known port was Jacksonville, Florida, where it docked Sept. 30 before making its way to San Juan, Puerto Rico, according to the most recently available information from the ship tracking website Maritime Traffic.

Coast Guard cutters and U.S. Navy planes were continuing the search amid exceptionally heavy waves while the more than 140-mile-an-hour winds of a Category 4 storm were “sitting right over it,” Fedor said.

The owners of the ship, the Sea Star Line, said the two lifeboats onboard could hold 43 people each. On Monday, the Coast Guard along with Sea Star concluded the ship had probably sunk after an oil sheen was spotted. It’s unclear what cargo the ship was carrying, but it would have been inside hundreds of heavy shipping containers.

The Washington Post, citing an email sent from the El Faro Thursday, said the ship began taking on water and then tilted to one side. Communications with the ship reportedly were lost after this.  

“We’ve been going with no sleep for four days,” Laurie Bobillot, whose daughter Danielle Randolph was aboard the ship, told the Washington Post on Sunday night from Jacksonville, where she and other family members of the crew gathered to wait for news regarding survivors.