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.

The 59-year-old man was arrested after a container ship struck an oil tanker in the North Sea on Monday. A crew member was presumed dead after an extensive search was called off.