The uniform of murdered policeman Keith Blakelock has been removed from Scotland Yard's crime museum for forensic examination.
Pc Blakelock's uniform has been in the museum since his death
The uniform has been held there since 40-year-old Pc Blakelock died during riots in 1985.
The examination of DNA on the clothing is part of a murder inquiry started in December 2003.
It comes after police found an "item" after digging up a garden Tottenham, north London last week.
The crime museum, which contains weapons and artefacts from notorious crimes, is not open to the public and is used to train police and forensic officers.
"We can confirm that Pc Blakelock's uniform has been removed from the New Scotland Yard crime museum," a police spokeswoman said.
"The uniform will be subjected to forensic testing as part of a new inquiry."
Pc Blakelock, a father of three, was murdered by a machete-wielding gang during the riot on the Broadwater Farm estate, Tottenham, in October 1985.
The disturbance was sparked by the death of Cynthia Jarrett, 49, who collapsed after four policemen burst into her home during a raid.
Pc Blakelock and his colleague Pc Richard Coombes were attacked when they went on to the estate to protect firefighters as the violence escalated.
Winston Silcott, Mark Braithwaite and Engin Raghip were convicted of the killing in 1987 but cleared on appeal.