In 1984 , a series of changes in the Pakistan Penal Code sections relating to blasphemy that , in essence , made it illegal for Ahmadis to preach their religion openly as Islam , leading to arrests and prosecutions . In 1984 , a series of changes in the Pakistan Penal Code sections relating to blasphemy were made , which , in essence , made it illegal for Ahmadis to preach their creed , leading to arrests and prosecutions .