Zoheir Ali Esmail, Shaykh Zoheir Ali Esmail has a Bsc in Accounting and Finance from the LSE in London, and an MA in Islamic Studies from Middlesex University. He studied Arabic at Damascus University and holds a PhD... Answered 6 years ago
Bismillah
Thank you for your question. Most of the Imams (as) died from poisoning and evidence for this is found in reports to that effect concerning the death of each Imam.
For further details please see Kitab al-Irshad of Shaykh al-Mufid.
May you always be successful