In March the family of Lance Corporal Foley paid the following tribute:
"Michael passed away while on operational duty in Afghanistan where he was very proud to be serving his country in support of our combined forces in this theatre of operations.
"He will be sorely missed by his family and friends and everyone privileged to serve with him both on his last tour and during his military career."
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Some 66 people have been killed after the plane they were travelling on crashed in southern Iran.
The letter calls for an end to harassment, abuse, and impunity in a world "ripe for change".
Police say that anyone who sees Whitehouse should not approach him, but instead call them on 999 and quote incident 23 of 18 February.