Exhumations have played a key role in high-profile cases including those of Dr Harold Shipman and James Hanratty.
Permission to exhume must be given by the land owner
And now police have begun to exhume the bodies of three women who died at the Parkfields care home in Butleigh, Somerset, to be tested for traces of drugs.
There are about 1,200 exhumations every year in the UK, but not all are part of criminal cases.
Licences can also be granted to people wishing to prove a familial link using DNA from dead relatives.
Others are exhumed to allow for new developments - for example, buildings or transport links on burial land.
When Greater Manchester Police decided to exhume several former patients of Harold Shipman, all eyes were on them.
Not least because it was the first time since the force was formed that it had exhumed a body.
As chief investigating officer Detective Superintendent Bernard Postles told the BBC: "That just indicates to you just how unusual it is to exhume a body".
Unusual, maybe, but vital to the Shipman case.
Forensic tests in that case found traces of diamorphine in the patients' remains, giving police vital evidence to bring 15 murder charges against the former GP.
Although in theory permission from the next of kin is not needed for an exhumation, it is always sought where possible.
Families themselves, like the police, coroner and anyone else, can apply for a licence to have a body exhumed with good reason.
In the Shipman case, it was his victims who were exhumed but in other cases it is the killer or suspected killer.
One example is that of infamous A6 murderer James Hanratty, who was exhumed in March 2001.
Hanratty was hanged after being convicted in 1962 for the shooting dead of scientist Michael Gregsten.
Calvi's death was initially put down to suicide until his exhumation
His family always maintained his innocence but DNA taken from his exhumed body matched two samples from the crime scene.
One of the first exhumations of a suspect was that of former nightclub doorman Joe Kappen in 2002.
He was suspected of the murder of three young women in south Wales in 1973 but had died in 1990 of lung cancer.
DNA from his exhumed body matched samples from one of the murder scenes.
Exhumations may also be ordered or requested when there is doubt about whether the cause of death was self-inflicted or down to foul play.
In 1982, Roberto Calvi, who was known as God's banker for his associations with the Vatican, was found hanged under Blackfriars Bridge with bricks in his pockets.
The verdict was suicide but, after lengthy protests by his family, Calvi's body was exhumed in 1998 so that a post mortem could be done.
Forensic tests showed Calvi's hands had never touched the bricks in his pockets and his neck showed none of the signs of death by hanging.
This evidence turned the case on its head and led to the launch of a murder inquiry.
Sometimes results from an exhumed body are less dramatic, but nonetheless vital to the family of the person involved.
When drug addict Rachel Whitear died in 2000 of a suspected heroin overdose, her parents used a picture of her body as a warning to youngsters.
No post mortem was carried out at the time and the coroner recorded an open verdict, but her parents were not satisfied with the evidence they had been given.
They eventually persuaded police to exhume her body.
No evidence of foul play was found, but the new forensic material collected was enough to help win the family a second inquest.