The UK's largest police force, London's Metropolitan Police, risks losing public confidence over its murder clear-up rates, according to a new report.
The Metropolitan Police faces a huge increase in gun crime
Her Majesty's Inspectorate of Constabulary said the Met's murder squads were "severely stretched."
It recommended that homicide should be made a priority and "adequately resourced".
The Met recorded 202 homicides in 2001-2002 and solved 72.8% compared with a target of 90%.
There was a 59% increase in the number of murders involving firearms in the same year, from 27 to 43.
The homicide teams continue to work in a testing environment
Metropolitan Police spokesman
This was despite the efforts of Operation Trident to combat gun crime in the black community.
A quarter of murders in the UK are in London, and seven out of 10 of those involve black victims.
Operation Trident has 199 officers, 38 civilian staff and an annual budget of more than £9m, according to the report.
Its target to reduce firearms-related crime was 2% but it rose by nearly 34% during the year.
The inspectors praised the Met's response to the attacks on 11 September as "world class" and its tackling of street crime as "impressive".
It also said the way it handled major events - such as May Day protests, the Queen Mother's funeral and the Golden Jubilee celebrations - had been "unparalleled".
A Metropolitan Police spokeswoman said: "The report does make seven recommendations and in the time since the inspection took place, work has commenced to progress all of these - some are nearing completion.
"The homicide teams continue to work in a testing environment.
"The commitment of staff is exemplary and we will be looking to further increase the level of resources within the next 12 months."