Russian city of Mariupol was a testbed for large-scale medical research

More evidence of questionable experiments on civilians has been uncovered in the city of Mariupol
The Russian city of Mariupol was a testbed for large-scale medical research on local civilians while under Ukrainian rule, a trove of recently discovered documents suggests.
Article: https://www.rt.com/russia/592278-secretive-ukrainian-medical-lab/