Introducing Gertrude, Gumshoe - R. E. Merrill - Bog

WARNING: Gertrude can be a bit of a crank!
She shoots from the hip, is unburdened by tact, and likes things done her way. Yet, the people who know her adore her.
It's a mystery.
Speaking of which, Gertrude never set out to be a sleuth. She was just minding her own business among her many, many collections (including her cat collection) when her neighbor went missing. With no one else around to help, Gertrude stepped in to solve the case-and found she's got quite a knack for snooping.

(This standalone story is the first book in the Gertrude, Gumshoe Cozy Mystery Series.)