This sounds FF'ish, after Notre Dame, setting the table for a religious war. Why do you write a letter that explains your plans?
And how is the letter suddently just "uncovered by The Sunday Times"?
In a letter to the Islamic State’s caliph Abu Bakr al-Baghdadi uncovered by The Sunday Times, six jihadist leaders describe how they will use a number of “crocodile cells” to acquire funds for terrorist operations through violent crime and perpetrate mass-casualty terrorist attacks against innocent European civilians.
The letter also describes how radical Islamic terrorists will be smuggled into Europe from the territory once occupied by al-Baghdadi’s shattered caliphate and the wider Middle East, Caucasus, and Central Asia regions posing as regular migrants.
Times article being picked up by several outlets
https://www.thetimes.co.uk/edition/news/isis-plans-to-copy-paris-atrocity-with-fresh-wave-of-carnage-qt6d0t82z
https://www.breitbart.com/europe/2019/04/16/revealed-isis-plan-series-paris-style-atrocities-across-europe/
https://newspunch.com/isis-series-paris-style-massacres-across-europe/