"Cold in the Grave" by Stephen Mertz (2018)

In Cold in the Grave (2018), Stephen Mertz reaches back forty years to 1978 to revisit the detective from his first novel, Some Die Hard. The earlier novel's protagonist, Rock Dugan, has become Kilroy. He's still a Vietnam vet and ex-Hollywood stuntman currently making ends meet as a private eye in Denver, but Kilroy is less meta than Dugan, making fewer references to Erle Stanley Gardner and Raymond Chandler than his predecessor. Rather than compare himself to his literary P.I. models, Kilroy follows in their footsteps. A rogue at times, a knight at others, honest with the goodhearted, willing to bend (and sometimes break) the law in the name of truth and justice (and his client's paycheck)—in short, he's everything a classic private eye should be, and he fulfills the role in spades.

Set in 1975, Cold in the Grave finds Kilroy on the trail of a missing woman. His client, Robert Pierpont, is concerned that the girl he likes, Cheryl Kaplin, may be in trouble.

"Some Die Hard" by Stephen Mertz (writing as Stephen Brett) (1978)

Originally written with a nod to the classic private eye novels that inspired him, Stephen Mertz's Some Die Hard (1978) has since become a classic in its own right. It's got everything you want out of a P.I. novel—a tough guy detective, an impossible locked-door murder, a contested will, squabbling inheritors, and gangsters and dames aplenty. But while Some Die Hard may follow in the footsteps of its forebears, it doesn't walk in their shadow. Mertz honors tradition in the best way possible, by crafting an intelligent and innovative mystery and bringing new surprises to the table. 42 years after its first publication, Some Die Hard still feels fresh and exciting.

The story begins with Rock Dugan, private eye, Vietnam vet and ex-Hollywood stunt man, taking a bus back to Denver from a job. As he's getting off the bus, the man in front of him turns around and bumps into him, then takes off running as two hoods chase him. The man doesn't get too far before he's hit by a cab. That's when Rock notices the man had slipped something into his book back on the bus—a letter addressed to Susan Court. Hand-delivering it to Ms. Court, Rock finds himself drawn into a family conflict. Susan has been cut out of her father's will, and now he plans to reverse the decision and reinstate her and cut out her brother, a drunken louse with lots of gambling debts. Rock agrees to accompany her home to Langdon Springs to look into things. But Rock's not there for more than a few hours before he finds himself deep in a murder case, and dodging thugs and local police who would rather he go back to Denver.