US Seventh Fleet Commander Vice Admiral Joseph Aucoin announced the commencement of an investigation into the fatal collision between the Navy destroyer USS Fitzgerald and a merchant vessel June 17.

The Fitzgerald collided with the container carrier ACX Crystal as it sailed into its home port in Yokosuka, Japan on Saturday afternoon. The Fitzgerald experienced extensive damage and flooding after the collision with the container ship. Seven US sailors died as a result of the collision.

There are discrepancies between the Navy and the merchant vessel about the time line of the incident and its aftermath.

“We owe it to our families and the Navy to understand what happened,” said Aucoin. “Under my authority, I am initiating a JAGMAN investigation into this collision, and I will appoint a flag officer to lead that investigation. There will also be a safety investigation.

“The US Coast Guard is to take the lead on the marine casualty investigation,” Aucoin added.

The damage to the Fitzgerald included a significant impact under the ship’s pilothouse on the starboard side and a large puncture below the ship’s waterline, opening the hull to the sea. The ship suffered severe damage rapidly flooding three large compartments that included one machinery room and two berthing areas for 116 crew.

“The commanding officer’s cabin was also directly hit,” Aucoin said, “trapping the CO inside.”

The crew responded heroically, according to Aucoin, taking steps to prevent the flooding from spreading which could have caused the ship to sink. The Navy ship made its way back to port safely under its own power.

“It could have been much worse,” Aucoin said.

Japanese Coast Guard ships and helicopters were the first on scene. The Japanese executed the first medevac, the ship’s commanding officer, Commander Bryce Benson.

There have been different accounts on the timing of the crash, with the cargo ship’s owners saying it happening at 1:30 AM while the US Navy claims the collision occurred at 2:20 AM. Also at issue is an abrupt U-turn the cargo vessel took either before or after the collision, depending on which time line is correct. Some experts speculate the maneuver was to examine what the cargo vessel hit. Others say if the U-turn occurred before the crash, foul play could have been afoot.

A Jane’s Intelligence Review expert suspects that the ACX Crystal was running on autopilot and nobody was on the bridge. “If anyone was on the bridge, they had no idea how to turn off the autopilot,” Steffan Watkins told DailyMail.com.

Meanwhile, Admiral Aucoin expects there to be several investigations into the incident. “We recognize that there are other organizations who have equities in this incident, and we expect they will conduct their own separate investigations,” he said. “More information on any further investigations will be forthcoming.”