The district court says there is a risk the man will flee or destroy evidence if released.
He is suspected of using a false document, a felony.
Caffa was boarded outside Trelleborg on March 6. The Swedish Transport Agency found serious safety deficiencies on board. The tanker Sea Owl I is also being held by Swedish authorities near Caffa. The master of that vessel is also in custody.
Both ships are suspected of sailing under a false flag.
