Is it permissible to issue a fatwa for the killing of a poet who insulted the Creator, Almighty and Exalted be He, in a country with a secular system, and is this ruling শরعي (religiously lawful) at all times?

The ruling of apostasy is a serious matter, and legal judgments are based upon it. Only scholars firmly grounded in knowledge delve into it. The implementation of the apostasy punishment is entrusted to the ruler or his deputy for the benefit of the people and to protect their lives, properties, and honors. If a Muslim apostatizes, his blood becomes lawful (i.e., he becomes subject to capital punishment), and his killing is for the Imam or his deputy. Whoever among the Muslims kills him (without the authority of the Imam or his deputy) shall be disciplined. In the absence of a ruler to implement the punishments, Muslims should treat the apostate as a disbeliever: they should not marry him, nor inherit from him, and his wife separates from him. They must strive to guide him and encourage his repentance.