Nosy Neighbors by Freya Sampson

Nothing brings neighbors together like someone else’s secrets… At Shelley House, the walls have ears, and they’re attached to a ragtag duo of busybodies ready to pry, snoop, and generally annoy their neighbors into solving a crime.
 
Seventy-seven-year-old Dorothy Darling has lived in Shelley House longer than any of the other residents, and if you take their word for it, she’s as cantankerous as they come. But Dorothy has her reasons for spying. And none of them require justifying herself to Kat Bennett. 
 
Twenty-five-year-old Kat has never known a place where she felt truly at home, and crumbling Shelley House is no different. Her neighbors find her prickly and unapproachable, but beneath her tough exterior, Kat’s plagued by a guilty secret from her past.
 
When their apartments face demolition, sworn enemies Kat and Dorothy agree on just one thing: they must save their historic building. But when someone plays dirty—and one of the residents is viciously taken down—Dorothy and Kat seek justice. The police close the investigation too soon, leaving it up to the unlikely amateur sleuths—with a playful Jack Russell terrier at their side—to restore peace in their community.