Two men have been arrested over the theft of an 82-year-old woman's body from a graveyard, detectives have said.
Police say they have not recovered Mrs Hammond's remains
The remains of Gladys Hammond, whose son-in-law helps to run a farm breeding guinea pigs for medical research, were dug up in Yoxall, near Lichfield.
The Coventry Animal Alliance claims that animal rights protester John Curtin, 41, was arrested at his home in the Hillfields area of the city.
Police said the arrests were made in Wolverhampton and Coventry.
Mrs Hammond's body was removed from her burial plot at St Peter's Church last week and Staffordshire Police said they have not recovered her remains.
It is thought that at least two people were involved in digging up the grave of Mrs Hammond, whose family have repeatedly been targeted by animal
Staffordshire Police said a 41-year-old man in Coventry and a 34-year-old man in Wolverhampton were arrested on Thursday morning.
Animal Alliance member Nancy Phipps, whose daughter Jill was crushed to death under a lorry during a protest at Coventry Airport in 1995, said Mr Curtin had been arrested at his home in Adelaide Street.
Mrs Phipps said: "John's door was knocked down this morning despite the fact he has had nothing to do with the Newchurch protest. The police are just on a fishing trip.
Police called in the coroner after the grave was desecrated
"John is well known in the movement and he's a campaigner and a good speaker. He has converted to Buddhism and he's a gentle person."
A police spokesman said: "In a pre-planned operation between Staffordshire Police and West Midlands Police this morning, officers have arrested two men.
"The men were taken to police stations in Staffordshire, where they will be interviewed.
"Officers are currently conducting searches and forensic tests at the addresses."
Mrs Hammond, who died in 1997, was the mother-in-law of Chris Hall, one of two brothers who run Darley Oaks Farm in Newchurch, Staffordshire.
The campaign against the Hall family by animal rights activists has included hate mail, malicious phone calls, hoax bombs, a paedophile smear campaign and arson attacks.
The arrest operation involved officers from Staffordshire Police's environmental protests unit, as well as the force's major investigations department and West Midlands police.