The Vatican was today rocked by a sex scandal reaching into Pope Benedict's household after a chorister was sacked for allegedly procuring male prostitutes for a papal gentleman-in-waiting.

Angelo Balducci, a Gentleman of His Holiness, was caught by police on a wiretap allegedly negotiating with Thomas Chinedu Ehiem, a 29-year-old Vatican chorister, over the specific physical details of men he wanted brought to him. Transcripts in the possession of the Guardian suggest that numerous men may have been procured for Balducci, at least one of whom was studying for the priesthood.

The explosive claims about Balducci's private life have caused grave embarrassment to the Vatican, which has yet to publicly comment on the affair.

While Catholicism does not condemn homosexuality outright, its teaching is that homosexual acts "are intrinsically disordered". The Catechism of the Catholic church states unequivocally: "Under no circumstances can they be approved."

Balducci was arrested on 10 February, suspected of involvement in widespread corruption. A senior Italian government official, he is alleged to have to steered public works contracts towards favoured bidders. He has not been charged.

It was during this investigation into corruption that wiretaps revealed his alleged sexual activity. In one conversation, Ehiem tells Balducci: "I saw your call when I was in the Vatican, because I was doing rehearsals … in the choir … in St Peter's." He then suggests Balducci meet a man who he describes is "two metres tall … 97 kilos … aged 33, completely active."

Balducci is also a senior adviser to the Congregation for the Evangelisation of Peoples, the department that oversees the Roman Catholic church's worldwide missionary activities.

Since 1995, he has been a member of one of the world's most exclusive fraternities – the Gentlemen of His Holiness, or Papal Gentlemen, the ceremonial ushers of the papal household. In the words of a 1968 ordinance, they are expected to "distinguish themselves for the good of souls and the glory of the name of the Lord".

According to a report by the Carabinieri for prosecutors in Florence investigating the corruption scandal, there was a hidden side to Balducci's life. "In order to organise casual encounters of a sexual nature, he availed himself of the intercession of two individuals who, it is maintained, may form part of an organised network, especially active in [Rome], of exploiters or at least facilitators of male prostitution."

It named one as Ehiem, a professional chorister born in Nigeria. According to Italian press reports, Ehiem, a member of the choir that sings in St Peters when the pope is not officiating, lost his job on Wednesday after details of the Florence investigation became known to the Vatican.

In an interview to be published tomorrow by the news magazine Panorama, Ehiem said he had been introduced to Balducci more than 10 years ago. He claims: "He asked me if I could procure other men for him. He told me he was married and that I had to do it in great secrecy."

There were conflicting accounts of how the Vatican might respond. According to one source, there was no provision for the dismissal of a Gentleman of His Holiness. Another said: "We shall wait for the judiciary's definitive verdict."

The transcripts imply that over a period of around five months in 2008, Ehiem procured for Balducci at least 10 contacts with, among others, "two black Cuban lads", a former male model from Naples, and a rugby player from Rome.

Balducci's lawyer, Franco Coppi, said tonight: "I have no comment. First, because we have more serious questions to tackle. Second, if these claims are correct, they regard his private life. It is disgraceful that these transcripts, which have nothing to do with the case, should have been spread about."

In January this year, the Carabinieri recorded an exchange in which Balducci and Ehiem discuss a seminarian, or student for the priesthood. Balducci is said to have asked: "Listen, have you spoken with the seminarian by any chance?" Ehiem says he is "probably at mass or something". On 11 January, Ehiem calls again to recommend "a colleague, a friend" of the seminarian because the latter is unavailable. He says the colleague is "better, taller, a bit taller than you". Later, Ehiem asks: "Can I send [him] around straight away?"

He asks where Balducci is. The adviser says: "Up at the seminary … where the cardinal lives." Ehiem replies: "He could get there within half an hour … the time it takes to catch a taxi and get there."