The Dynacom-owned tanker disappeared from radar last month off the coast of Angola, adding to fears that pirates in the area were extending their reach.

The tanker was subsequently found the following week with all crew alive and accounted for, but with some injuries.

Angola's navy refused to believe pirates had come so far down the coast and claimed the hijacking was a farce.

"It was all faked, there have been no acts of piracy in Angolan waters," Captain Augusto Alfredo told Reuters.

"What happened on January 18, when we lost contact with the ship, was that the crew disabled the communications on purpose. There was no hijacking."

These accusations have since been disregarded, with an Interpol-led multinational response team, Liberian and Ghanaian authorities jointly investigating the incident.

Investigations into the events were still ongoing, but the Liberian Registry concluded the vessel was hijacked by pirates after examining the vessel and its crew.

According to a report, the pirates disabled the vessel's communication systems and painted over any identifying features on the vessel before conducting three separate ship-to-ship transfers of cargo, amounting to over 12,000 tonnes.

One crew member was stabbed during the hijacking, while others were beaten.

Liberia said it would continue to work with authorities in Ghana, Nigeria and Angola to find the pirates responsible.