On 27 April 1772, Reza Khan was arrested and Murshidabad went through a revolution. But it seemed nobody exactly knew why it was necessary and who had it set in motion. The Nawab was possibly the first to ask the question. In a letter to Hastings he asked to know what grave offences the Khan had committed and to stress that Reza Khan had both served him faithfully and had the Company's interest at heart.

It was not surprising that the Nawab should ask why Reza Khan had been arrested, for the whole affair had been shrouded in secrecy. Middleton knew nothing beyond what Hastings had said in his letter of 24 April, and to the Khan himself Hastings had written only to say that he was sorry that in view of the latest orders of the Directors he could not continue the cordial relations which his predecessors had maintained with him. The Khan was also asked to refer to Middleton for further details while Middleton was asked to avoid personal meeting with the Khan. Reza Khan then wrote to Hastings through Ali Ibrahim Khan asking for a translation of the Company's orders, but Hastings in his replies of 13 May did no more than assure the Khan and the Nawab that the particulars would be sent soon. Even the Calcutta Council were left in ignorance until 28 April, when they were told that the Khan was under arrest and on his way to Calcutta.