12.04.2010 and the murder reference was answered in the affirmative and his sentence of death was confirmed. His criminal appeal was also dismissed by this Court on 27.10.2016 and his conviction and sentence were maintained. The review petition filed by Ghulam Abbas against the said judgment of this Court was also dismissed on 18.07.2018. Same was the fate of his mercy petition filed before the President of Pakistan which was rejected on 22.04.2019. 11. Consequently, black warrants were issued, and his execution was fixed for 18.06.2019. In this backdrop, Mst. Noor Jehan (mother of Ghulam Abbas) filed the instant Constitution Petition No. 9 of 2019 under Article 184(3) of the Constitution of the Islamic Republic of Pakistan, 1973 (Constitution) before this Court for staying the execution of black warrants on the grounds that Ghulam Abbas suffers from intellectual disability and mental illness which predate his confinement in jail; that he has severe learning disability since his childhood; that he is suffering from repeated seizures/fits; that he has a documented history of mental illness during his confinement in jail; that he has been prescribed antipsychotic medication. While pleading these circumstances, she has prayed for staying the execution of black warrants and assessment and evaluation of Ghulam Abbas by a Special Medical Board. While entertaining the petition, the then Hon'ble Chief Justice of Pakistan vide order dated 17.06.2019 stayed the execution of death sentence of Ghulam Abbas and directed the office to club the instant petition with C.R.P. No. 420 of 2016 (Imdad Ali's case). 12. In view of the facts narrated hereinabove, the important legal questions which emanate from these petitions are as under:(i) How should the trial Court deal with the plea of an accused that he/she was suffering from mental illness at the time of commission of offence? (ii) How should the trial Court deal with the claim that due to mental illness, an accused is incapable of making his/her defence? (iii) Whether a mentally ill condemned prisoner should be executed? 13. In view of serious and important legal questions involved in these petitions, notices were issued to the Advocates General of Provinces of Sindh, Khyber Pakhtunkhwa, Balochistan and Federal Capital Territory. No formal notices were required to be issued to the Government of the Punjab and the Federation since they already stood represented in C.R.P. No. 424 of 2016 and Crl. R.P. No. 170 of 2016. 14. Considering the sensitivity and significance of the issues involved, by order dated 17.09.2020, Brigadier (Retd) Professor Mowadat Hussain Rana, a renowned Professor of Psychiatry and Barrister Haider Rasul Mirza, Advocate Supreme Court of Pakistan (ASC) were asked to assist the Court as amici curiae. ARGUMENTS 15. Learned counsel for the condemned prisoners Imdad Ali, Mst. Kaneezan Bibi and Ghulam Abbas has vehemently contended that these convicts are lodged in death cell for a considerably long period of time and they are suffering from acute mental illnesses. He stated that the Medical Board constituted by this Court has given a categoric opinion that Imdad Ali is suffering from Schizophrenia, Mst.