Earlier this year the Metropolitan Police released figures showing there were a total of 393 murders between 1997 and 2018 which remained unsolved (or using their definition, ‘undetected’).
The number of undetected murders peaked in around 2001 before decreasing to single figures between 2011 and 2015, then increasing again to a new peak in 2018. The percentage of total cases that remain undetected also varies by year. If we compare undetected murders to the available yearly figures for total homicides (including manslaughter), the undetected cases vary from between 4% (2014) and 25% (2018). See end of post for sources of figures.
However, it is important to note that the figures for the most recent years should be treated with caution because many murder cases take months or years to be ‘detected’. Older years are therefore more stable, whereas more recent years could be expected to drop significantly in future.
The police also gave some interesting details about the investigative process in relation to unsolved cases, which it insists are ‘never closed’:
- If unsolved after 28 days, a homicide investigation is independently reviewed by specialist officers from the Met’s Serious Crime Review Group. These reviews are intended to support senior investigating officers progress investigations by providing independent assessment of all lines of inquiry.
- Where all reasonable lines of inquiry have been progressed and a case remains unsolved, it is formally presented to a dedicated panel chaired by a Commander. The panel makes a decision whether the investigation should be put on hold.
- If put on hold, the investigation is then subject to a review every two years by the Serious Crime Review Group. This review aims to identify any new investigative opportunities or development in techniques, including forensics, or if any new information has emerged.
Detective Chief Superintendent Richard Woods, the head of the Homicide and Major Crime Command, explains: “There is a huge amount of work taking place on unsolved murders.
“There are between 15-20 cases subject to a full cold case review at any one time.
“Behind every unsolved murder there is a family looking for answers. We are committed to doing all we can to solve these cases.
“Through 24-month reviews we look to see if anything new has emerged, whether it be information, forensic evidence, or changed allegiances. If new information or evidence comes to light, we will assess this and progress any viable lines of inquiry.”
The police FOI giving figures for undetected murders dates back to 12/02/2019.
The government’s historical data for crimes recorded by each force (back to 1990) refers only to homicide (not murder). The most recent statistics are published by the ONS.