A detailed search is taking place in a Staffordshire churchyard where animal activists have been accused of digging up the remains of an 82-year-old woman.
Police have described the desecration as "callous and sick"
Gladys Hammond's burial plot was disturbed at St Peter's Church, Yoxall, seven years after her death.
Mrs Hammond's family breed guinea pigs for medical research and MP Michael Fabricant has connected the incident with a four-year campaign against them.
Police say they are investigating a possible link to animal activists.
The breeding of guinea pigs by the Hall family at Darley Oaks Farm in Newchurch has been the focus of a long campaign by protesters.
Det Chief Insp Nick Baker said: "Gladys Hammond was a relative of the Hall family who have been the subject of protests and intimidation by animal rights protesters."
He added: "I believe there is somebody out there who is able to point the finger at the callous and sick individuals who carried out this desecration."
Forensic experts and scenes of crime officers are now combing the churchyard, where a churchgoer found the grave desecrated on Thursday afternoon.
Lichfield MP Michael Fabricant said on Friday the incident was the latest in a long series of attacks by "so-called animal rights activists" on owners, workers, relatives and friends of people associated with Darley Oaks Farm.
The Halls have bred guinea pigs at Darley Oaks Farm for many years
He told the House of Commons in January about a letter he had received from the Hall family detailing attacks on relatives.
"This is the culmination of a whole series of incidents affecting the Hall family and local villagers," Mr Fabricant said.
A spokeswoman for Save the Newchurch Guinea Pigs (SNGP) said she was shocked at the discovery and distanced the campaign group from the incident.
"Save the Newchurch Guinea Pigs has been peacefully protesting for the last five years to end the cruel breeding of guinea pigs.
"This incident has nothing to do with our group."
In a statement released through Staffordshire Police on Saturday, Mrs Hammond's family said they were distressed by the desecration.
The statement read: "The family is devastated and distraught that the grave of a very much loved mother and grandmother has been violated and desecrated in this way.
"She was devoted to her family and fortunately did not have to experience in her lifetime the distress we as a family have suffered in recent years at the hands of animal extremists.
"The callous and sick individuals who desecrated the grave of an 82-year-old lady must be caught.
"We as a family would urge anyone who has information about this despicable offence to come forward."