Why Do People Kill?

In the final episode of our summer specials, forensic psychologist Kerry Daynes talks to Steve Keogh, a retired Metropolitan Police detective inspector who spent twelve years on Scotland Yard's Murder Investigation Team and helped convict around 100 killers. Steve reveals how murder squads achieve an extraordinary 90% clear-up rate, why smartphones have become a detective's most valuable piece of evidence, and what working the devastating aftermath of the 7/7 London bombings taught him about trauma and resilience. He also shares the theory it took him thirty years to develop: that virtually every murder is driven by one of just three underlying motives. It's a rare look at homicide investigation from the other side of the interview room.

Key psychological themesThis episode explores: the three drivers of murder — emotion, power and control, and gain • trauma, resilience and delayed grief in frontline policing • coercive control and domestic homicide • missed warning signs in mental-health-related killings • digital evidence and behavioural profiling

Contributors featured in this episode• Kerry Daynes — Forensic psychologist, presenter, and author of Dark Side of the Mind and What Lies Buried.

• Steve Keogh — Retired Metropolitan Police detective inspector, Scotland Yard Murder Investigation Team; author and host of Murder Unpacked.

What you'll learn in this episode• Why murder has a 90% clear-up rate in the UK, far higher than crimes like burglary, and how a team of up to 50 detectives makes that possible

• How cuts to the Met's murder teams, from 29 down to 18, have left detectives permanently playing catch-up

• Why nearly a third of London's murders are domestic-violence related, and why a woman's greatest homicide risk comes from a partner or ex-partner

• What it was really like working the Edgware Road bomb scene for two weeks after 7/7, and why the psychological toll didn't hit Steve until years later

• Why phones, not CCTV or forensics, are the single most valuable piece of evidence in a modern murder inquiry

• Steve's theory that almost every killing is driven by one of three motives: an emotional trigger, the desire to feel powerful, or material gain

• Why Steve believes many domestic and mental-health-related homicides were preventable, and the warning signs that kept being missed

Relevant links and further reading• Kerry Daynes — Dark Side of the Mind (Endeavour, 2019)