The questions over last week’s incident in which a pair of US Navy boats and 10 sailors strayed into Iranian waters continue to grow, as the Pentagon’s narrative on a “navigational error” is thrown into serious doubt.

The Pentagon initially claimed mechanical problems, but after the boats were returned changed its story to claim the sailors had no idea they were in Iranian waters. Today, however, Iran revealed that the GPS devices on the two US boats were in perfect working order at the time, and they had no reason not to know they were in Iranian waters.

The riverine boats were to go from Kuwait to Bahrain on a training exercise. They were to go through a practice refueling with a US Navy cutter in the Persian Gulf, but never arrived, and instead wandered into the water off the coast of Iran’s Farsi Island, the site of a large naval base.

The sailors were detained overnight and released, along with their boats. Though Iranian officials accepted the narrative that the boats made an accidental incursion into their waters, the Pentagon still hasn’t offered a plausible excuse for how this could’ve possibly happened.