Which preposition to use with malpractice

of Occurrences 5%

Indeed, Commodore Perry says, "I could only induce the commissioners to agree to this article, by endeavoring to convince them that it would save the Japanese Government much trouble if an American agent were to reside at one or both of the ports opened by the treaty, to whom complaints might be made of any malpractice of the United States citizens who might visit the Japanese dominions."

with Occurrences 1%

" "Surely," said Eustachio, "provided always that the servant is a man of exemplary character, and that he presumes not upon his lord's withdrawal to another sphere, trusting thereby to commit malpractices with impunity, but doth, on the contrary, deport himself as ever in his great taskmaster's eye.

Which preposition to use with  malpractice