The man, who is in his 30s, drove off the Poland ferry on New Year's Day but was stopped at customs control. In his car sat another person who did not have permission to enter Sweden, and at the same time two other passengers were discovered trying to leave the ferry on foot. They too did not have the right documents, and it turned out that they had gone on the ferry together with the 30-year-old.
Since then, the investigation has grown significantly.
"We checked what trips he had made back in time and have so far identified twelve trips. In total, he has smuggled in 49 people who have not had the right to stay in Sweden, says Lena-Marie Bergström, prosecutor in the case.
May have been paid
According to the prosecutor, all passengers have come from Uzbekistan, but where they have gone after arriving in Karlskrona is not clear.
"We have tried to get information about what documents they have had, where they have gone and what right they have to be here. A witness we have talked to has told us that he came to seek asylum in Sweden, says Lena-Marie Bergström.
A European investigation order has been sent to Poland and the Czech Republic, where the suspect has been in the past, to help with the further investigation.
"Among other things, to obtain financial information about whether he has received payment for these trips. We have indications that this has been the case.
The man denies any wrongdoing, and says in interrogation that on every trip he checked that the passengers have so-called Schengen visas. He is now in custody on suspicion of probable cause for twelve counts of aggravated human smuggling.