Sofia's military district prosecutor's office has opened pre-trial proceedings over the attack on the Malta-flagged motor vessel CHELSEA 3. The attack took place in Bulgaria's exclusive economic zone in the Black Sea, the prosecution service said.

Drones hit the ship on 13 October, 17 nautical miles east of Byala. All 15 crew members were rescued.

The investigation's wording says an order was given in October 2026 to kill the civilians on board, meaning the crew, and to destroy property on a large scale, meaning the ship itself. It says this breaks the rules of international law on the conduct of war.

The case began with a report from the foundation Bulgarian Lawyers for Human Rights and the association Bulgarian Helsinki Committee. The Sofia City Prosecutor's Office referred it to the military prosecutors. The two groups say the rules of international law on the conduct of war were broken in Bulgaria's exclusive economic zone.

The chief secretary of the Interior Ministry must see that the ministry carries out the prosecutors' instructions on the steps that are its job. These include tracing witnesses, finding out where CHELSEA 3 is, and taking other steps to clarify the case and identify anyone who may have been involved.

Investigators must also gather evidence on who owns the ship, who was on board, where it was heading and why, and what it was carrying: cargo and/or passengers.

Another ship was attacked on 13 October: the HS Dignity, which flies the flag of Guinea-Bissau. A drone hit it and it sank 17 nautical miles east of Shabla. Seven days earlier, sea and air drones hit two other merchant ships in the same area.