The grave of an 87-year-old woman whose family has been the target of animal rights protesters has been desecrated.
The damage to Gladys Hammond's burial plot was discovered on Thursday at St Peter's Church, Yoxall, Staffordshire. Her remains had been disturbed.
Her family's connection to a farm where guinea pigs are bred for research has led to a campaign against them.
Police said they were investigating possible links to groups opposed to activities at the farm in Newchurch.
Mrs Hammond's family has been the target of protests in recent years because of their connection with the Darley Oaks Farm.
Det Chief Insp Nick Baker told reporters at the scene that they were keeping an open mind about the motive.
"It is above any issue of protest or cause. This is sick and depraved. We should just focus on that."
Asked about possible links to animal rights protests, he added: "It is one of the lines of inquiry we are looking into.
"Gladys Hammond was a relative of the Hall family who have been the subject of protests and intimidation by animal rights protesters."
The officer refused to elaborate on the extent of the damage to the grave but described it as a "very sensitive issue" which had distressed Mrs Hammond's family.
Diocesan officials said the damage went "way beyond" petty vandalism. The site has been cordoned off while forensic teams carry out an investigation.
Rev Jenny Lister, the vicar at St Peter's, reported the matter to police after being informed by a member of the public who was visiting the churchyard.
The Bishop of Wolverhampton, the Right Reverend Michael Bourke, said: "I offer my condolences to the family of the deceased who must be very distressed and I know the church will do all it can to support them.
"I hope that those who have desecrated the grave in this way will soon be brought to justice."
Gavin Drake, a spokesman
for the Diocese of Lichfield, said: "We are sickened by the actions of
these people. This is not the way to behave. This isn't petty vandalism. This
is a very serious crime."