From https://t.me/pravdaGerashchenko_en

The #Swedish_Coast_Guard boarded and detained #Russian "shadow fleet" tanker #Flora_1 on suspicion of environmental crime, it said in a statement.

Early on Thursday, a Coast Guard surveillance aircraft detected a mineral oil spill east of #Gotland, which was over 12 kilometers long at the time. #Flora_1 was identified early on as being of interest to the investigation.