New Zealand marine activist Pete Bethune's case against the Sea Shepherd and its founder Paul Watson begins in court today in the US.
Mr Bethune took a case to force Sea Shepherd to pay US$500,000 (NZ$616,600) he says he is owed for the initial purchase of his boat, the Ady Gil.
The boat was rammed by a Japanese whalers while taking part in a Sea Shepherd campaign in the South Ocean whale sanctuary in 2010.
Paul Watson will be a witness in court despite him having just skipped bail from Germany where he was being held following an extradition order issued by the Costa Rican authorities.
"I am extremely sad that I have been forced to bring this case to court against an organisation that I loved and a man that I had great respect for," said Bethune in a statement before the case.