The family of an 82-year-old woman whose body was dug up from a churchyard have received threatening letters, police have disclosed.
Police called in the coroner after the desecration
Detectives said several letters were sent to the Hall family who own a farm that breeds animals for research.
The writer of the letters claims to have the remains of Gladys Hammond, but police cannot verify this.
Her body was thought to have been taken by animal rights extremists because of her family's links to the farm.
Officers say at this stage they cannot link the letters to the desecration of Mrs Hammond's grave at St Peter's Church in Yoxall, Staffordshire.
Det Chief Insp Nick Baker said: "We deplore the actions of those who have sent these letters.
Malicious and intimidating
"The family are still extremely distraught and this offence only adds to their upset at a difficult and emotional time.
"I would urge anyone who knows who the perpetrators are, or has any information they believe may help this inquiry, to contact us."
The letters, which are said to be similar to previous malicious and intimidating letters received by the family from animal rights extremists, are being tested for forensic evidence.
Mrs Hammond's remains have not been recovered.
Two men, who were arrested in connection with the inquiry, have been released on police bail.
A service was held on Saturday to rededicate Mrs Hammond's grave at the churchyard.
The Darley Oaks Farm, in nearby Newchurch, breeds guinea pigs for use in medical research and has been the scene of regular protests over the last five years.
The farm is run by Mrs Hammond's son-in-law Christopher Hall and his brother John.
John Hall told the BBC's Inside Out programme that what has happened is unbelieveable.
The remains were disturbed seven years after Mrs Hammond's death
"To desecrate lovely Gladys's grave is an absolute outrage, it just goes beyond belief really," he said.
"They call us scum but I wonder if they really know the meaning of the word.
"Our first priority is to have Gladys returned so that she can go in her restful place in the churchyard and after that's happened, then we will need to look at the future and decide what we intend to do.
"We are not monsters and none of our staff are monsters, we are just ordinary people doing a job that some people don't like."
Protesters are also interviewed in the programme, which will be broadcast in the West Midlands on BBC One at 1930 BST on Monday.