NEW DELHI (AP) — The pirate “mother ship” sunk last week by the Indian navy was actually a Thai fishing trawler seized hours earlier by pirates, a maritime agency said Wednesday. The Indian navy defended its actions, saying it fired in self-defense.

One Thai crew member died when the Indian frigate INS Tabar fired on the boat in the Gulf of Aden last week, according to Noel Choong, who heads the International Maritime Bureau’s piracy reporting center in Kuala Lumpur.

One Cambodian crew member was rescued four days later by passing fishermen, but 14 other sailors remain missing, Choong said. The maritime bureau received a report on the apparent mistake late Tuesday from Bangkok-based Sirichai Fisheries, which owned the trawler, the Ekawat Nava5, he said.

“The Indian navy assumed it was a pirate vessel because they may have seen armed pirates on board the boat which had been hijacked earlier,” Choong said.

India’s navy said last week that the INS Tabar, which began patrolling the gulf on Nov. 2, battled a pirate “mother ship” on Nov. 18, setting the vessel ablaze.