Counter terrorism officers are searching addresses in Birmingham, Coventry and Leicester.
The note was written to a bodyguard and was signed by the princess and Princes William and Harry.
Live ammunition - such as hand grenades - has been found at the bottom of rivers and canals by a Leicestershire family.
David Devlin is jailed for 22 years after breaking into the house of a woman who scratched his face.
Send us your questions about the area and we'll investigate.
Leicestershire battle to a competitive total on a mixed opening day of their Division Two game against Durham.
Leicestershire host Durham in County Championship Division Two - live BBC local radio commentary
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