McKinnon's new novel is Sister Dear.
At CrimeReads she tagged ten favorite psychological thrillers with sibling rivalry at the heart of them, including:
This Is How I Lied by Heather GudenkaufRead about another entry on the list.
More than two decades ago, the body of teenager Eve Knox was found in nearby caves by her best friend Maggie, and Eve’s sister, Nola. When potential new evidence is uncovered, Maggie, now a detective and seven months pregnant, is determined to find out what happened to Eve that night. Full of dark twists and questionable characters with even more questionable motives, Gudenkauf is a master at writing small-town creepy.
--Marshal Zeringue