When Sunnis and shias burnt the graves of saliheen of each other and no one from the grave came to help them.
Ibn Kathir mentioned about the fitna between Shias and Sunnis in 443 h.
في صفر منها وقع الحرب بين الروافض والسنة، فقتل من الفريقين خلق كثير، وذلك أن الروافض نصبوا أبراجا وكتبوا عيها بالذهب: محمد وعلي خير البشر، فمن رضي فقد شكر، ومن أبى فقد كفر، فأنكرت السنة إقران علي مع محمد ﷺ في هذا، فنشبت الحرب بينهم، واستمر القتال بينهم إلى ربيع الأول، فقتل رجل هاشمي فدفن عند الإمام أحمد، ورجع السنة من دفنه فنهبوا مشهد موسى بن جعفر، وأحرقوا ضريح موسى، ومحمد الجواد، وقبور بنى بوية، وقبور من هناك من الوزراء.
وأحرق قبر جعفر بن المنصور، ومحمد الأمين، وأمه زبيدة، وقبور كثيرة جدا.
وانتشرت الفتنة وتجاوزوا الحدود، وقد قابلهم أولئك الرافضة أيضا بمفاسد كثيرة، وبعثروا قبورا قديمة، وأحرقوا من فيها من الصالحين، حتى هموا بقبر الإمام أحمد، فمنعهم النقيب، وخاف من غائلة ذلك.
In Safar of this year fight started between Rafadih and ahlus sunnah. And many people from both sides were killed. The reason was that rawafdih set up pillars and wrote on them from gold that Muhammad (peace be upon him) and Ali (radhiAllahanho) are khayr ul Bashr, whoever agreed did shukr and whoever rejected did kufr.
Ahlus sunnah rejected that Ali (radhiAllahanho) should be matched with Prophet peace be upon him and fight started (from safar) to Rabi ul awwal. One Hashmi was killed who was buried near Imam Ahmad, Ahlus sunnah came back after burying and (in revenge) looted the shrine of Musa bin Jafar. And burnt the tomb of Musa, Muhammad Jawad and graves of Bani Boiya and graves of their Vazirs. And also burnt gave of Jafar bin Munsoor, Muhammad al Ameen and his Mother Zubaida and many others.
The fight spread and crossed the lines. Rafadhis also responded them with many evils, scattered the old graves and burnt the saliheen of the graves until they came to the grave of Imam Ahmad. The Naqeeb prevented them to do so as he feared from the fitna (of burning the grave of Imam Ahmad).
al Bidaya wal Nihaya the year 443 h
Both parties went too far in hate and crossed limits. And did worst thing of Burning graves and killings but no one from the grave dwellers helped them.