The excavator driver was brought in for questioning, family members told foreign-based satellite channels. Some people even said he had been arrested, but this could not be independently verified.

Image Reza Shah Pahlavi, who became shah in 1925. Credit... Associated Press

The excitement built as news of the mummy spread across the country, becoming a popular rallying point against Iran’s clerical government and quickly setting off alarms in high places. People started gathering at the shrine, calling out for Reza Shah. One video shows supporters of the Tehran soccer club Persepolis shouting, “Long live Reza Shah” during a game.

Persian-language satellite channels operating from abroad heralded the discovery of the mummy as a sign that the Islamic republic’s days were numbered. Reza Shah’s grandson, the crown prince Reza Pahlavi, who lives in the Washington suburbs, wrote a statement calling for an independent investigation. In all corners of Iran, at supermarkets, bus stops, clinics or wherever, the return of the shah was hotly debated.

“This is Reza Shah, no doubt,” said Akbar, who was selling Islamic jewelry in the bazaar near the shrine and who refused to give his family name to an inquisitive foreigner whose intentions were unclear. “We Iranians are superstitious, and I personally believe his return is a message. That message is: ‘Correct the mess.’ ”