Every ninety seconds someone is reported missing in the UK. Most return, but some do not. This book is about those who stay missing.

The police are unable to investigate every case fully. But the missing always leave behind traces – clues as to who they might have been and where they might have gone.

Dave Grimstead, a retired detective inspector, has built Locate International: a remarkable team of volunteers – oceanographers and genealogists, forensic linguists and vintage clothes experts, students and retirees – all united by a desire to follow the clues wherever they lead.

Someone Must Know brings readers into the heart of stories that cross decades and international borders in the search for the truth. In a world where the questions begin with a scrap of wet paper in a pocket, an old dress or a faded photograph, the answers are by turns devastating, poignant and deeply mysterious.

Through riveting cold cases, from the tall man washed up at sea with weights tied to his ankles, to the mother who left home one morning and slipped through the cracks of everyday life, Someone Must Know is a study in how to reconstruct whole lives from fragments of evidence, for people who are gone but do not deserve to be forgotten.

'Heart-rending but utterly uplifting' PROFESSOR LADY SUE BLACK, author of All That Remains

'Gripping and compassionate' VAL MCDERMID

‘Fascinating’ LYNDA LA PLANTE CBE

'Enthralling ... carried me along in a tidal wave of page-turning intrigue' DUNCAN HARDING

'By the end of this book you'll want to join Locate's team yourself' ANGELA GALLOP

© Dave Grimstead 2026 (P) Penguin Audio 2026