Killer on Argyle Street — Michael Raleigh

A Chicago PI hunts for a missing kid who fell in with the wrong crowd: “Raleigh presents a genuine good guy in the luckless Whelan” (Publishers Weekly).
 
An elderly woman has asked private investigator Paul Whelan to look into the disappearance of Tony Blanchard -- a young man she'd taken in after his parents died. Instead, Whelan discovers a string of murders, all tied to a car-theft ring.
 
All the evidence suggests that Tony is dead as well, but Whelan keeps digging until he finds himself surrounded by a dangerous maze of silent witnesses, crooked cops, and people willing to kill to keep the truth from surfacing. When a friend from Whelan's past emerges -- a friend Whelan thought long dead -- his investigation takes a dangerous turn: one that brings him no closer to Tony, and a lot closer to his own demise.
 
“Raleigh's Paul Whelan series brings to mind the late Ross McDonald's Lew Archer novels . . . Read Whelan now; he won't be a secret much longer.” -- Booklist