Tusk quotes him, reporters resign. Who's Jacek Muranski?

The planet of Polish politics lives on Onet concerning Karol Nawrocki, who, respective years ago - as a bodyguard of the Grand Hotel in Sopot - was expected to be active in bringing in sex workers at the request of guests. The case was referred to by Freak fighter and erstwhile convict Jacek Muranski, who in an interview with TVP described the alleged cooperation of future PiS candidate for president with "Big Bu". Who is the man that even Prime Minister Donald Tusk quoted?