A spokesman said on condition of anonymity in accordance with police policy that federal police with search warrants boarded the Steve Irwin and the Bob Barker, ships belonging to the activist group Sea Shepherd Conservation Society, as the result of a “formal referral from Japanese authorities.” He gave no further details, including on what basis the warrant was issued.

The search took place in Hobart, Tasmania where the ships docked Saturday after returning from their pursuit of Japanese whalers in their annual, three-month hunt for the sea mammals.