"Crash and burn" by Alison Bruce

An isolated, abandoned bungalow north of Cambridge is burnt down. 2 bodies are found - one new, and one under the floorboards, decades old. Ronnie (Veronica) investigates. She lives with her brother Alex and nephew Noah, 10 (his mother died). Malakei is in the team - young and single, living with his protective aunt. Nathan Paignton (nerdy brother of naughty suspect Alfie, 15) is suspected to be the victim. When Mariel was 2, she and her mother were abducted. Her mother Jacky wasn't seen again. Mariel was left in Trumpington St, where she now works. Chris Good, the son of the bungalow owner (a builder), had disappeared on the same night 20 years before. Mariel thinks she recognises the bungalow in the news article so she contacts the police.

Investigations reveal that the newer body is indeed Nathan's and that he could have started the fire. Alfie befriends Noah while he's walking from school, pretending he's Noah's uncle Owen. Questioned, Alfie says he did it to see if Ronnie is to be trusted. He confesses to Ronnie that Nathan lit the fire to stop Alfie getting into more trobule in the bungalow. Noah does have an uncle Owen, who he's never met. Ronnie arranges a meeting. 2 other bodies are found under the bungalow - women who were kidnapped for a ransom when Jacky disappeared in 2008. Connections emerge between the dead women and Chris Good. Nathan's father Steve, who owns a garage, is interviewed because Jacky had her car mended there. After (it's his PoV now), he writes letters while taking lots of pills with alcohol. He phones Ronnie, who suspects something's wrong. They find him in time. While recovering in hospital he tells the police everything. He'd been in debt and had gone to Chris Good. He ended up abducting women for him, and collecting the ransom money. He spared Mariel and killed Good, putting the body under "an ugly 1998 Fiat Multipla" in his back yard. They go to Mariel. She'd recalled a man saying "Dooboe" and had always wondered what it meant. Malakei says it might have been "Do both". It sparks memories. She recalls her father at the bungalow telling Chris Good to "Do both" (i.e. kill his wife and daughter). She confronts him, secretly recording the conversation. He tells her he married too early and family life got in the way of business. The father's arrested. Alfie stops bunking off school.

I know many of the locations. I like her internal monologues, though the vocabulary register doesn't always sound appropriate. They're not central to the plot. Nor is the Owen incident. I presume it's there for the benefit of a future book in the series. It's well-enough handled all the same. The final twist is rather implausible. The writing's effective - the flashiest phrase is "her forehead flickering with a frown".