An odd story at a Catholic news site:
ROME — The remains of St. Peter may have been and possibly still could be buried in catacombs under the Mausoleum of St. Helena after being moved from the Vatican hillside during anti-Christian persecutions in the third century, according to a paper published recently by three Italian researchers.
Labeling their conclusions as “conjecture,” the researchers suggested archaeologists could “validate” their findings with “excavation campaigns”; however, a leading expert in Christian archaeology and a member of the Pontifical Commission for Sacred Archaeology told Vatican News that the researchers’ hypothesis was “unacceptable.”
Emperor Constantine would never have gone through so much logistical trouble building St. Peter’s Basilica in the early fourth century “if it had not been contingent upon the presence of the venerated remains” below, where the saint’s tomb had been venerated since early Christian times, Vincenzo Fiocchi Nicolai told Vatican News May 30.
“It is clear,” he said, “that Peter’s remains were found in the place of the original burial site on the Vatican hill when the formidable Constantinian basilica was built, the biggest basilica ever established in the city,” he said, adding that if later the remains had been moved “ad catacumbasto,” then that refers to a cemetery on the Appian Way, later called, the catacombs of St. Sebastian.
A previous Pope thought the saint's bones had already been discovered, but the means of identification sounds dubious:
While scholars are certain St. Peter’s ancient tomb was located on the Vatican hill where he had died a martyr and where Constantine ordered a basilica be built, his remains have been a source of much controversy and mystery.
St. Paul VI announced in 1968 that the “relics” of St. Peter had been “identified in a way which we can hold to be convincing,” after bones were discovered following excavations of the necropolis under St. Peter’s Basilica, which began in the 1940s near a monument erected in the fourth century to honor St. Peter.
The pope had cases of the relics placed beneath the basilica’s main altar and in his private chapel in the Apostolic Palace. Scientists have confirmed the remains are those of a 60- to 70-year-old robust male, according to Vatican News.