Which preposition to use with wallower

in Occurrences 1%

News and comments which did nothing to lessen the pride and insolence of the Jubaland tribesmen, of the Wak tribesmen, of the bold Zubhier sons of the desert, nor to strike terror to the hearts of the murderers of Captain Aylmer and Mr. Jenner, of slave-traders, game-poachers, raiders, wallowers in slaughter....

Which preposition to use with  wallower