'The Push' by Claire McGowan
Six couples, part of a pre-natal class gather at the swanky home of one of the couples after the birth of their babies to celebrate and someone falls from a balcony to their death. Though it appears to have been merely a "fall", an intrepid Detective Sergeant Alison Hegarty suspects that might not be the entire story. And of course, she's right. The 'fall' was in fact a 'push' but there are so many suspects, and so many secrets ...
As the story develops, it's clear that the attendees at the party all have something to hide, so they're not particularly forthcoming with the police. This wasn't exactly a locked room mystery, but definitely a close cousin. The perpetrator is obviously someone who was at the party, but the mystery is that as the action develops we realize that almost everyone has a something akin to a motive. I listened to this one, and was never bored, but also never quite as engaged as I might have been. We got the POVs of at least one half of all six couples, which was interesting, but made it tough to become particularly attached to any single person. The person to whom we should have been most attached---because she was the only POV in first person---was somewhat annoying and difficult to relate to. Jax's (that's her name) conflict was that she was a thirty-seven-year-old with a much younger (twenty-four-year-old) partner, Aaron, who is also very good-looking; so most of her internal monologue involved agonizing over what people must think of her, or about how "ridiculous" she must seem. Oh ... and there's also the mysterious happenings at work and at home, that she irrationally, decides not to share with Aaron.
Apart from investigating the crime, the DS is undergoing her own challenge---she and her partner want to get pregnant and can't. So, while she watches these new parents lie and evade, she also envies, relates to, and studies them, not just as suspects, but as people who have the one thing she wants most.
The narrator was great, and the story was good. I recommend for a quick mystery fix.