Looking for a novel or short story about an immortal shapeshifter cop/detective

Question

I'm looking for a novel or short story that I read in the late 90s or early 2000s; I remember that it was from the point of view of a detective or cop who was tracking a serial killer.

The protagonist was a member of a secret species of shapeshifters, and chose to live as a human. When he found the serial killer, he discovered that it was another member of his species--but young and psychotic.

Since his species can regenerate from any injury, he defeats the murderer by shifting himself into a fluid form and perfectly enveloping him until he suffocates--a tactic that is only possible because the protagonist is relatively old and experienced with his abilities.

And that's all I remember about it. The aspects I remember result in such generic search terms that I haven't had any luck with Google. I suspect I might have read it in an anthology, or perhaps in a magazine like Asimov's.

Answer 1

The story is Hardshell by Dean R. Koontz, previously identified as the answer to Short story: Cop chasing serial killer, both are shape shifting aliens. I read it in Koontz's anthology Strange Highways.

The story is exactly as you describe. The scene where the protagonist (Frank) kills the serial killer (Skagg) is:

The inescapable embrace with which Frank enfolded Skagg was not merely that of an executioner but that of a brother and a priest; he was gently conveying Skagg out of this life, and he was doing so with some measure of the regret with which he watched ordinary men suffer and expire from accident and disease. Death was the unwelcome son of chaos in a universe woefully in need of order.

For the next hour, with diminishing energy, Skagg writhed and thrashed and struggled. A man could not have endured for so long without oxygen, but Skagg was not a man; he was both more and less than human.

Frank was patient. Hundreds of years of self-enforced adaptation to the limits of the human condition had taught him extreme patience. He held fast to Skagg a full half hour after the last detectable sign of life ebbed from the mad creature, and Skagg was as encapsulated as an object dipped in preserving bronze or eternally frozen in a cube of amber