David Marshall QPM MSc recently retired from the Metropolitan Police with over 30 year's service, including postings on the International and Organised Crime Branch and Paedophile Unit at New Scotland Yard. For the last nine years as DCI he was head of the Specialist Crime Directorates Child Abuse Investigation Command's major investigation team responsible for the investigation of complex abuse, child homicides and suspicious deaths in London. In this position he had experience of over fifty child homicides and suspicious deaths. He regularly lectures on the NPIA Investigating Sudden Childhood Death Programme, is a faculty member on the University of Warwick Advanced Course in the Management of Unexpected Childhood Death and was a UK representative on the Interpol Specialist Group on Crimes against Children. He has contributed to national police guidance, written a number of published articles and presented on numerous conferences and courses in the UK and abroad.