In view of the recent discussion of the topic, I thought this might be of interest - happened to come across it while reading on Talavera.

Plasencia, 9th July, 1809. To the Right Hon. John Villiers

' MY DEAR VlLLIERS, '
I have received your letter of the 5th, and I am perfectly
satisfied with any notice taken by the Government of the
present acts of enmity committed by the people of Portugal
on the troops, which I fear that the latter deserve but too
well.
' We must have some general rule of proceeding in cases
of criminal outrages by British Officers and soldiers, by
which the individuals guilty of them may be brought to
early punishment. As matters are now conducted, the
Government and I stand complimenting each other, while
no notice is taken of the murderer; and the example of
his early trial and punishment is lost to the troops.
( The artilleryman who has committed the murder at
Cascaes must be tried according to the laws of the country,
or for a military offence under the Articles of War. My
opinion is that he, and all guilty of similar offences,
ought to be tried (I mean tried in earnest, and not as the
Officers of the th were tried) according to the laws
of the country ; but if the Government prefer that we should
take cognizance of these offences, as being of a military
nature, we will do so at once in every case ; but they must
assist us in obliging the witnesses to come forward and
give their testimony on oath, to which I find they have
great objections.

' Believe me, &c.
' ARTHUR WELLESLEY.

Cheers

C