The captain of the Solong cargo ship who was arrested after crashing into an oil tanker off the English coast is a Russian national, the vessel’s owner said Wednesday, as maritime experts search for answers.

A port official said he was told the North Sea collision produced "a massive fireball" and the cargo ship's owner said one crew member was missing.

British authorities have arrested the captain of a cargo ship as they investigate the cause of a fatal crash between the vessel and an oil tanker shipping jet fuel for the U.S. military in the North Sea.