The U.S. Navy’s investigation into the capture of ten American sailors in January “concluded that Iran violated international law” when it seized the sailors, the United States Chief of Naval Operations announced Thursday.

In his prepared remarks, Admiral John Richardson explained the ways Iran violated international law. The U.S. ships, which were captured in what Iran claimed was its territorial waters, “had every right to be where they were that day. The investigation concluded that Iran violated international law by impeding the boats’ innocent passage transit, and they violated our sovereign immunity by boarding, searching, and seizing the boats, and by photographing and video recording the crew.”

However, Richardson said, “the bulk of the investigation” focused on preventing similar incidents from recurring. The Defense Department announced that the Navy would be taking disciplinary action against nine officers and sailors for their actions leading up to and during the incident.

At a Senate Armed Services Committee hearing in March, Secretary of Defense Ashton Carter deviated from his prepared remarks to blast Iran for actions that “were outrageous, unprofessional and inconsistent with international law.”

Shortly after the seizure of the sailors and their two boats, Senate Armed Services Committee chairman John McCain (R – Ariz.),  a former prisoner of war, raised the possibility that the capture of sailors violated the United States’ immunity. “Under international law, sovereign immune vessels like navy ships and boats do not lose their sovereign immune status when they are in distress at sea,” he said. “Under international law, sovereign immune naval vessels are exempt from detention, boarding, or search. Their crews are not subject to detention or arrest.”

Iran’s broadcast of videos of the captured sailors also raised questions over whether Iran violated the Geneva Conventions’ rules regarding the treatment of prisoners.

Subsequent to the sailors’ release, Iran portrayed their capture as a victory against the United States. Iranian Supreme Leader Ayatollah Ali Khamenei proclaimed that the naval forces who seized the sailors did “God’s deed,” and subsequently issued medals to the commanders involved. Iran released the sailors after claiming that the United States apologized for the incident. Iran’s Islamic Revolutionary Guard Corps announced plans to build a statue to commemorate the capture of the American sailors.

[Photo: Eric C. Tretter / Wikimedia ]