One of the longest chases in anti-poaching maritime history ended on April 6 when the Thunder sunk off the West African coast after being followed for thousands of nautical miles by the environmentalist group Sea Shepherd.

Ships from the Sea Shepherd Conservation Society, an international environmental group, hunted down the Thunder for 10,260 nautical miles until the ship sunk in the North Atlantic, according to the statement by Sea Shepherd.

Captain Paul Watson, the group's founder, recounted how the hunt for the poaching ship, part of a group called the Bandit Six, started in the Southern Ocean off Antartica four months ago, traversing the South Atlantic and Indian Oceans and into the North Atlantic.

The Sea Shepherd ships Bob Barker and Sam Simon, with Captain Peter Hammarstedt and Captain Sid Chakravarty respectively in command, followed the Thunder, which had been illegally fishing for Patagonian toothfish, for 110 days.

In an interesting turn of events, the Thunder sent a distress signal and the Bob Barker and Sam Simon found the ship sinking. All 40 crewmembers (30 Indonesian, seven Spanish, two Chilean and one Portuguese) were taken aboard the Sam Simon. The two ships took the men and other evidence to Sao Tome.

Although the chase ended peacefully, Sea Shepherd believes the crew of the Thunder deliberately scuttled the ship, according to CNN.

"I'm 100% confident that the captain of the Thunder destroyed his own ship," Captain Hammarstedt told CNN via phone.

"Usually what happens when a vessel is sinking is the master will ensure all compartments and hatches are shut so as to maintain buoyancy," he explained. "On the Thunder, all the hatches had been opened, including the hatch leading to the fish hold."

Inside the hold, which was a quarter full, the Sea Shepherd crews found toothfish. They also obtained computers and mobile devices from the ship.

Adam Burling, spokesman for Sea Shepherd, said the Thunder was spotted off Antartica four months ago, dropping its net, which contained around $3 million worth of toothfish. The Interpol had issued a "purple notice" asking for information on the poacher ship back in 2013.

The Sea Shepherd statement explained the ships' operations were part of a larger effort called Operation Icefish, which hoped to curtail illegal fishing in the waters around the South Pole.

Aside from the sinking of the Thunder, Sea Shepherd has also captured two other vessels from the Bandit Six, the Viking and the Kunlun.

The Sea Shepherd group has a mission "to end the destruction of habitat and slaughter of wildlife in the world's oceans in order to conserve and protect ecosystems and species."

Video of the sinking of the Thunder: