Police in northern Greece are investigating a cemetery worker's testimony that a woman revived in her grave shortly after being buried and called for help, only to die before she could be extracted.

Police officials say the man and two people visiting the cemetery said they heard banging and a muffled call from inside the 49-year-old cancer patient's grave late Thursday, an hour after her funeral.

By the time the coffin was dug up and smashed open, the woman showed no further signs of life. A doctor summoned to Peraia cemetery outside Thessaloniki pronounced her dead.

The mother of two had been first declared dead at a private Thessaloniki clinic early Thursday. A coroner will examine the body.

The officials spoke on condition of anonymity because they weren't authorized to brief journalists about it.