Sentence:  The killer , if in our present group , would certainly be interested in knowing that much , and even though with the fingerprint evidence what it was I could see no way he could <WSD>use</WSD> this bit of information to improve on his situation , there might always be some way . 
Meaning of the word marked with <WSD> tags:  put into service; make work or employ for a particular purpose or for its inherent or natural purpose