Greek experts have rejected reports that a woman, alleged to have woken in her grave and cried for help – only to die before she could be disinterred – was alive when she was buried.

After examining the woman’s body, forensic pathologists said it showed no signs of suffocation as suggested by witnesses who said they heard banging and muffled shouts when they visited an adjacent grave on Thursday.

“There was no sign of death by asphyxiation in the coffin,” said Matthaios Tsougas, one of two coroners who conducted the autopsy. “The hour of death was early Thursday morning, which corresponds with what was written on the death certificate.”

The tests were ordered after gravediggers alerted to the commotion frantically began extracting the coffin at a cemetery in the northern town of Perraia. But by the time the body had been removed, doctors who had rushed to the scene pronounced the woman dead.

“When the ambulance arrived, gravediggers were still throwing dirt off the grave. As soon as the body was exhumed a cardiogram was conducted that confirmed the woman was dead,” Chrissi Matsikoudi, the emergency services doctor who examined the corpse, was quoted as saying.

“The body was in a state of rigor mortis … it is impossible that only a short time before the deceased had been crying for help when we found her in [that] state,” she said. “Her eyes, it is true, were open but the coroner can give an explanation for that. As far as her mouth is concerned, I cannot say it was open, it was relaxed.”

Witnesses reported seeing the body of the unidentified woman with her arms raised, and told the Greek media they believed she had died of asphyxiation.

The 49-year-old mother-of-two had been buried in a funeral attended by family members barely an hour before. She had been declared dead earlier in the day by doctors at a private clinic in nearby Thessaloniki, northern Greece’s capital. “A cardiogram has rendered it certain that the patient above is no longer alive,” concluded a medical announcement released to the press.

But Nikos Dialynas, a lawyer representing the woman’s family, said his clients believed she had come out of a coma after being buried. The relatives were now considering filing a complaint against the physicians who had treated her.

“We have the testimonies of three people, who are not related to the deceased and which are serious and very concrete [in detail],” he said. “They include an employee who worked at the cemetery. They hadn’t escaped from some psychiatric hospital nor were they [suffering], optically or acoustically, from delusions. What they say is very plain, very clear.”

Police contacted by the Guardian said the forensic pathologists would conduct an autopsy to determine the exact time of the woman’s death.

“A second coroner will also be present for reasons of impartiality,” said a police officer in Thessaloniki. “This is the first time in living memory that a body has been exhumed because, rightfully or wrongfully, the person is believed not to have died. It is a very particular case and we have launched an investigation.”

In a statement following the post-mortem, the coroners said the woman’s open eyes were “a natural reaction of the human body in death.”