Fifth in the Ed and Am series, but last for several years (Brown worked on other projects from '52-58.) Having opened their own detective agency, Ed and Am start by taking cases passed along by former employer Starlock. One day a girl walks into their door, in fear of murder caused by Martians. The pair don't take her too seriously... until she winds up dead.
Similar books by other authors
Martians and Misplaced Clues
Used availability for Fredric Brown's Death Has Many Doors
August 2004 : USA Paperback
December 2021 : USA, Canada Kindle edition