An experienced specialist in criminal fiscal law, tax and customs law, finance law, administrative enforcement, and the liability of directors and shareholders under tax law.

His unique experience arises from more than ten years of working for tax authorities. In the period 1992–2007, Mr Olkiewicz headed the Preliminary Investigations Department at the Tax Audit Authority in Poznań. He acted as a financial authority in preliminary proceedings and before courts as a public prosecutor in criminal fiscal cases.

He has conducted many training courses in criminal fiscal law for tax authority personnel and for professional lawyers: public prosecutors, attorneys-at-law or judges, including the Supreme Court justices. He participated and conducted several training sessions attended by the US Treasury Department.