Cruel Acts is the 8th in the Maeve Kerrigan series of police procedurals set in London. As you can guess, as the series is named Maeve Kerrigan, she's the Detective protagonist. Her partner is Josh Derwent and together they've worked out an effective partnership. Though she is good with people and he is decidedly not, both are intelligent and driven and extremely good at their job, which is why they've been tasked with a delicate job. A convicted killer, Leo Stone, is about to win his appeal based on jury misconduct. Leo was convicted of killing Sara Grey and suspected of killing another.