More than 30 body parts have been stored by Cambridgeshire police, a report said.
The 35 samples were kept from murder investigations, suspicious and unexplained deaths.
A study by the Association of Chief Police Officers, which found 500 samples were held by forces in England, Wales and Northern Ireland, said there may be a “legal requirement” to retain samples.
They were stored until convicted prisoners served their sentences.
A Cambridgeshire police spokeswoman said: “The force, in partnership with the Coroner’s Office and the Strategic Health Service, carried out an audit of human tissue retained as part of investigations into sudden, unexplained or suspicious deaths.
“This audit was conducted following a change in the Human Tissue Audit which means we no longer need to retain these items.
“Police family liaison officers contacted the families involved to ensure they had the necessary support and advice throughout the process.”
An audit found some of the samples nationally dated back as far as 1960.