Why people kill

Why did he do it? Over the last few weeks, many of us have asked that question following a series of horrifying acts of violence that have been difficult to comprehend.

Why was 15-year-old Harvey Willgoose fatally stabbed at a school in Sheffield? Why did Axel Rudakubana slaughter three girls at a children’s dance class in Southport last summer? And why did the father and stepmother of ten-year-old Sara Sharif abuse, torture and murder her? 

Violent deaths are so shocking and alarming it’s natural that we search for explanations. But in the early stages, as details are pieced together and information about suspects isn’t known or publicly available, those answers often can’t be found. It’s not until the case comes to court that the full story can be told.

For two years I’ve been collecting details of court cases to try to understand more about why people kill. My focus was on London, where every year there are between 100 and 150 homicides – about 20 per cent of the annual total across England and Wales.