A Swedish court has sentenced a 27-year-old German man to one year's imprisonment for stealing toxic substances from a university where he was a student.

The Uppsala District Court on Friday said Gurkan Korkmaz used the alias LarryFlow to offer lethal substances like ricin on dark-web online markets, but added that it could not be proven he actually sold the substances.

Swedish police started the investigation in the fall of 2015 after receiving tips from U.S. police.

Korkmaz, who pleaded innocent, was ordered expelled from Sweden and banned from returning for five years.