How did Onet get receipts on Nawrockie? A well-known professor: “They print material illegally provided by secret services on orders from PO superiors”

In an article published on Wednesday, Onet.pl portal informs that Karol Nawrocki has 2 apartments. Information about the second (e.g. the number in the Perpetual Book) may have come from the case file of the examination conducted by the service prior to the granting of the safety certificate. Could journalists have come into possession of details another than erstwhile they received papers from the interior safety Agency?