SOLVED. SciFi - Private Detective find that society has been infiltrated by aliens appearing to be humans (like in "They Live"), starts committing random acts of violence against the aliens [s]

[Patnel]

English language, adult, read in the mid-1990's, and I believe it was published around the same time. The M/C is an adult male, private detective, who loses a gig to a large detective agency and when he visits that agency, he realized that their massive filing cabinets are filled with scrap paper, nothing useful. Somehow, he comes to find that aliens have infiltrated society, and are running that detective agency, among other things. The rest of the book is him assassinating various aliens who are disguised as politicians, law enforcement, etc. I think it takes place largely in California or the Southwest.

[Lobstergirl, au gratin]

Inhuman Beings?

Former cop Goodwin Armstrong, 44, is a divorced San Francisco PI battling the forces of a chain franchise detective agency, Security Concerns, when psychic Ronda Rabin, aka Princess Dulay, hires him. She claims aliens have invaded the U.S. and are planning a hostile takeover. The rest of Carroll's second novel (after Top Dog) is a by-the-numbers run that uncovers the aliens among us in the San Francisco police chief and mayor and their missing wives. Mysterious communication failures, blackouts, a plunging elevator, a seagull attack and assorted arsons preceded by blue flashes bring Armstrong to reporter Gilmore Ford, who steps in to help when it appears the alien takeover is rapidly moving to the White House.....

[Patnel]

That's definitely it, I recognize the cover...and all of the details given in the description. This is becoming my favorite place on the interwebs. Thanks, yet again, to Lobstergirl!

[Lobstergirl, au gratin]

You're welcome.