Did Ameerul Momineen (peace be upon him) maintain good relations with the killers of Hazrat Fatima Zahra (peace be upon her)?
The animosity of Ameerul Momineen (peace be upon him) for those who oppressed Hazrat Fatima Zahra (peace be upon her) is not a matter of doubt or debate. In fact, his hostility towards them, because of the heinous nature of the atrocities committed by them, is a well-known and documented fact. However, in order to conceal those crimes, the opponents of Shias often raise such baseless objections so that the masses do not believe in what actually transpired.
Here is a concise reply with some proofs from the books of renowned Ahle Tasannun scholars who are considered to be among their extremely revered and reliable personalities in the field of Islamic history and traditions:
- Muslim Ibn Hajjaaj Neyshapoori writes: Umar, in the presence of Usman Ibn Affaan, Abd al-Rahmaan Ibn Awf, Zubair Ibn Awaam and Saad Ibn Abi Waqqaas, while addressing Abbas Ibn Abd al-Muttalib and Imam Ali (peace be upon him) said: “When the Holy Prophet (peace be upon him and his progeny) passed away, Abu Bakr came to power and both of you considered him to be a liar, sinner, conspirer and a treacherous person. When Abu Bakr died and I became his successor, you considered me also, just like him, a liar, sinner, conspirer and treacherous.” 
- Muhammad Ibn Ismail Bukhari writes on the authority of Ayesha: “Ali (peace be upon him) introduced Umar as a tyrannical and despotic person; he refused to meet Umar Ibn Khattaab and was extremely uncomfortable with the presence of Umar in a gathering.” 
- Umar Ibn Khattaab, on an expedition to Syria, told Abdullah Ibn Abbas about Imam Ali (peace be upon him): “I have a complaint against your cousin. I requested him to accompany me to Syria but he refused. Your cousin seems to be forever uncomfortable with me. What could be the reason according to you?” 
- Both Bukhaari and Muslim have recorded: “Hazrat Fatima (peace be upon her) was angry with Abu Bakr for this (usurpation of Fadak). She expressed her dissatisfaction with him and severed all contacts with him and did not speak to him till she left for her heavenly abode. When she departed from this world, her husband Ali (peace be upon him) buried her at night. He did not allow Abu Bakr (to be informed) about it and recited the funeral prayers himself.” 
These are only few instances which are mentioned in the books of Ahle Tasannun which clearly establish that Imam Ali (peace be upon him) had severed his relations with the Shaikhain. Even after these, if someone tries to prove that he was on good terms with them, then he is either completely ignorant about history or has an ulterior motive to achieve some worldly or political gains.
Few questions to those who claim that Imam Ali (peace be upon him) was on good terms with the Shaikhain:
- If someone believes that they were liars, sinners, conspirers and treacherous, then will he continue to be on good terms with them?
- Why did Imam Ali (peace be upon him) refrain from meeting or even coming face-to-face with them and was discomforted even with their presence?
- Why did Imam Ali (peace be upon him) not participate in battles along with them?
- Why did Imam Ali (peace be upon him) bury Hazrat Fatima Zahra (peace be upon her) at night and did not inform them about her demise?
- Why did Hazrat Fatima Zahra (peace be upon her) express her displeasure and not speak to them till she left for her heavenly abode?
- Can calling them liars, sinners, conspirers and treacherous be considered as their praise and glorification?
- In one of his arguments, Ameerul Momineen (peace be upon him) labelled their actions as extremely sinful and also said that they deliberately opposed the orders of the Holy Prophet (peace be upon him and his progeny).  Does this qualify as their praise?
- Whatever Ameerul Momineen (peace be upon him) has expressed in his sermon of Shiqshiqiyyah, will that also be regarded as their praise?
Do the aforementioned narrations and proofs leave any further scope for a person to believe that Ameerul Momineen (peace be upon him) had cordial relations with those who oppressed Hazrat Fatima Zahra (peace be upon her)? While these were only few examples from Ahle Tasannun sources, there are a number of traditions and historical narrations in Shia sources to prove that Ameerul Momineen (peace be upon him) did not have even an iota of sympathy towards them, let alone things like paying allegiance to them or praying behind them. Woe be unto prejudice!
 Saheeh Muslim, p. 832, Kitaab al-Jehaad wa al-Seyar, Baab Hukm al-Fayy, H. 4552
 Saheeh al-Bukhaari, p. 843, Kitaab al-Maghaazi, Baab Ghazwah Khayber, H. 4240-4241
 Sharh Nahj al-Balaagha, vol. 12, p. 78
 Saheeh al-Bukhaari, p. 843, H. 4240-4241; Saheeh Muslim, p. 833, H. 4555
 Al-Ehtejaaj, vol. 1, p. 392; Al-Kaafi, vol. 8, p. 59, H 21