Story highlights The collision between the Fitzgerald and the ACX Crystal on June 17 claimed the lives of seven US sailors

The initial findings are just the first stage in what is expected to be a lengthy inquiry

(CNN) Preliminary findings in the investigation into the collision between the USS Fitzgerald and a Philippine cargo ship off the coast of Japan in June suggest the accident was caused by multiple errors by the Fitzgerald's crew and a failure to take action in the minutes leading to the collision, according to two defense officials.

"They did nothing until the last second," one official said. "A slew of things went wrong." A second official said the crash "will wind up being our (the US Navy's) fault."

The collision between the Fitzgerald, a guided-missile destroyer, and the ACX Crystal on June 17 claimed the lives of seven US sailors. It took place 56 nautical miles off the coast of Honshu, Japan, in an area heavily traveled by commercial shipping.

The initial findings are just the first stage in what is expected to be a lengthy inquiry. Both officials said the initial investigation found that the Fitzgerald crew failed to understand and acknowledge the cargo ship was approaching and failed to take any action necessary to avoid the collision. It's also not clear if the crew ever called the commanding officer to come to the bridge.

The officials say investigators are also looking at the possibility that the ship was traveling at a higher speed than expected to reach a location it was due to arrive at the next day.

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