From Thriller Picture Library #363, May 1961. Reprinted as Catch Me A Killer in #3, August 1966.
Getting an office above a jazz club because he liked the music, John Steel wasn't looking for a client yet but a week after meeting the jazz combo playing below, he gets one as the lead musician is accused of murdering a wealthy industrialist while trying to rob him. The combo had been playing a gig at a party given by the deceased and someone is claiming to have seen everything. Steel has considerable doubts.