The assassin was widely regarded as a mentally unstable melancholic, unrestrained in deeds. Piekarski's most probable cause for the assassination was fame and recognition; the successful assassination of Henry IV in Paris (1610) by François Ravaillac served as motivation for his actions. For the appropriate moment Piekarski waited patiently ten years. At trial he did not deny the crime he committed and heavily insulted the monarch, whilst blaming himself for the failed regicide. Piekarski was executed in a similar manner as Ravaillac on 27 November 1620 in Warsaw; he was publicly humiliated, tortured and his body torn apart by horses. The dismembered remains were subsequently burned and their ashes scattered by a cannon.