Don Pierino Gelmini is one of the church's best-known faces on Italian television, a close friend of top politicians including former prime minister Silvio Berlusconi, a rent-a-quote figure with right-wing views on drugs and family values.

In 2004, while still Prime Minister, Mr Berlusconi gave the 80-year-old priest, founder of Comunita Incontro, a public gift of 10 billion lira (�3.5m) for the organisation's work.

But yesterday La Stampa newspaper revealed that the priest has been under investigation on suspicion of sexually molesting young people, for more than six months. "It seems that the accusations are numerous and coherent, " the paper reported. "They revolve around a closed community in which a figure of enormous charisma seems not to have restricted himself to taking care of souls."

The priest's accusers are former residents of Comunita Incontro's centres with a history of drug use. But the magistrates have also interviewed many other possible witnesses, as well as Father Gelmini himself.

No details of the accusations have leaked to the media. Notoriously indiscreet when politicians are under investigation, in this case, perhaps thanks to the power of the church in Italian public life, the magistrates have kept the investigation under wraps.

A friend of the priest, Alessandro Meluzzi, said: "We are anguished, but are pleased to carry the cross that has been thrown on a man who has always served Christ, the church and the lowest of the low." The accusations, he added, came from "a small group of lads who were expelled from the community, who had all the typical problems of drug addicts, and of behaviour and personality as well."

As news of the investigation broke, right-wing politicians rushed to the priest's defence. Maria Burani Procaccini, spokesman on families and children for Forza Italia, Berlusconi's party, said: "In our hearts we say that Don Gelmini is a saint. And we ask the media not to murder the innocent."