Funeral Prayer for one who committed suicide

Q: Is a Funeral Prayer to be offered on someone who intentionally killed himself with a pistol even though he had good posts such as a teacher or police officer and no one knows the reasons behind the suicide? If the answer is the affirmative, how can this be justified despite the authentically reported Hadith stating that whoever kills himself shall abide forever in Hellfire? Moreover, the Messenger (peace be upon him) said regarding Qizman who fought with the Muslims in the battle of Uhud and killed eight of the Kafirs (disbelievers): "He is in Hellfire"; because Qizman was wounded and when his injury became extremely painful, he took an arrow from his own quiver and killed himself therewith. Please mention the proofs that support your answer.Besides, is the Funeral Prayer to be offered on someone who made Zina (sexual intercourse outside marriage) with his paternal uncle's wife, killed his uncle with a knife, carried him at night, put him in a distant place, and burnt him along with the wife but was then arrested and killed as Had (prescribed penalty) was applied against him? Is a Funeral Prayer to be offered on such a person despite the saying of Allah (Exalted be He): And whoever kills a believer intentionally, his recompense is Hell to abide therein; and the Wrath and the Curse of Allâh are upon him, and a great punishment is prepared for him. Please clarify this issue in the light of the proofs that your Eminence has. I am aware that the Messenger of Allah (peace be upon him) offered the Funeral Prayer for the lady that committed Zina and requested that Had be applied against her and that her confession and desire to be penalized by being stoned to death was regarded as Tawbah (repentance to Allah) for the Messenger (peace be upon him) said: She has made such a repentance that if it were to be divided over seventy from the people of Madinah, it would have sufficed them. On the contrary, those who killed themselves did not make any Tawbah. Similarly, murderers are keen to hide their crimes and it is only Allah (Exalted be He) who helps the authorities to arrest them. May Allah help you to say the truth and peace be upon you.

A: According to the Madh-hab (School of Jurisprudence) of Ahl-ul-Sunnah wal-Jama`ah (those adhering to the Sunnah and the Muslim community) amongst the Sahabah (Companions of the Prophet, peace be upon him) and the Salaf (righteous predecessors) who followed them, those who commit a major sin such as murder or suicide are not Kafirs (disbelievers) and thus, the Funeral Prayer is to be offered for them. Proof of this is that the Prophet (peace be upon him) ordered Muslims to offer the Funeral Prayer on someone who misappropriated booty in the path of Allah (Exalted be He). It is related in the Musnad (Book of Hadith compilation) of (Part No. 8; Page No. 396)  Imam Ahmad on the authority of Zayd ibn Khalid Al-Juhany (may Allah be pleased with him): A Muslim man died on the Day of Khaybar. They mentioned the matter to the Messenger of Allah (peace be upon him) and he said: Offer the Funeral prayer for your companion. When the faces of the people looked perplexed, he said: Your companion misappropriated booty in the path of Allah (Exalted be He). We searched his belongings and found some Jewish beads not worth two dirhams. However, the Hadith mentioned above signifies that the Muslims' Imam (ruler) should not offer a Funeral Prayer for such persons.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.