Police in northern Greece say they are investigating reports that a woman woke up to find herself buried in a coffin, only to die before being rescued.
Several people visiting the cemetery, near Thessaloniki, told police they had heard banging and muffled shouting from inside the woman's grave, an hour after her funeral on Thursday.
By the time the coffin was dug up, the woman, 45, was found dead.
She had earlier been declared dead by doctors treating her for cancer.
Her funeral was held at a cemetery in Peraia, a small town 22km (16 miles) south of Thessaloniki, Greece's main city in the north.
Shortly after the last relatives left the cemetery, residents and a group of children playing outside reportedly heard a female voice shouting for help from inside the grave.
They called the police, and began digging up the grave to save her but she had suffocated to death inside the coffin, Greek media reported.
However, a doctor who was at the scene and examined the woman's body, said she had been dead for hours and could not have been revived.
"I just don't believe it," Chrissi Matsikoudi told the Greek television channel MEGA.
"We did several tests including one for heart failure on the body," she said.
It would have been impossible for "someone in a state of rigor mortis to have been shouting and hitting the coffin like that," she added.
A coroner is expected to examine the body.
Meanwhile, relatives of the dead woman say they are considering filing a complaint against the doctors responsible for her treatment at the cancer clinic.