ZAGREB, Croatia (AP) — A Croatian army helicopter on Monday plunged into the Adriatic Sea, killing one crew member while the search is underway for the other, the country’s defense minister said.

Damir Krsticevic told reporters that an investigation has been launched to determine the cause of the crash Monday in a central area of Croatia’s Adriatic Sea coastline.

Krsticevic said an “intense” search is ongoing for the missing crew member.