The Marine Corps confirmed Thursday that it has officially concluded the search for wreckage and the 12 Hawaii Marines killed when two CH-53E Super Stallion helicopters crashed off Oahu’s North Shore due to unknown reasons Jan. 14.

The parents of one missing Marine, crew chief Sgt. Dillon Semolina, said the search actually ended April 4 after it was extended a few days by the commandant of the Marine Corps, Gen. Robert Neller.

Human remains discovered during search operations led to the positive identification of nine of the 12 Marines, Marine Corps spokesman Capt. Tim Irish said in a release.

Remains of Semolina, Sgt. Adam Schoeller and Cpl. Christopher Orlando were not recovered, Irish said. “Significant wreckage” from both helicopters was recovered, he said.

Witnesses reported seeing a fireball at sea the night the choppers crashed. No mayday call for help was made. The debris field was described as covering several square miles.

Semolina’s parents, Mike and Lisa De La Cruz, criticized the Marines for what they say was a waste of time in training divers for dives that never occurred because the wreckage site at 300 to 340 feet was too deep and with the recovery ship, USNS Salvor, at one point sitting in port for 11 days waiting on maintenance, including generator repairs.

“The (Marine Corps) commandant finally ordered them to purchase a new generator and get it on the ship,” Mike De La Cruz said. All the while, sea motion was dispersing the remains and wreckage on the seafloor, the Minnesota couple maintains.

The De La Cruzes said the Salvor searched on just 17 of 84 days. The Marine Corps said frequently unfavorable sea conditions prevented searches.

“No time was wasted,” Marine Corps spokeswoman Capt. Cassandra Gesecki said. “U.S. Navy dive teams immediately supported the initial search and rescue effort and began the underwater search phase, ultimately locating the mishap site.”

As more advanced search equipment arrived on island, it was determined the wreckage depth exceeded safe manned-diving limits, she said, and at that point a Remotely Operated Vehicle team was deployed.