Although he was very careful never to leave a fingerprint at the scene of a crime, he had the habit of putting his ear to a window or a keyhole to check if anybody was at home before breaking in, thus leaving behind his ear prints.
Ehkki see mees tegutses kuriteopaigal äärmiselt ettevaatlikult — ta ei jätnud kunagi endast maha ühtegi sõrmejälge —, oli tal kombeks panna oma kõrv aknale või võtmeaugule, tegemaks enne sissemurdmist kindlaks, et kedagi kodus ei oleks. Nõnda jäid temast maha kõrvajäljed.