Rome, Italy (CNN) -- A Nigerian man who sang in a Vatican choir arranged gay liaisons for an Italian government official who served in the unpaid role of papal usher, according to transcripts of wiretaps collected by Italian authorities.

The wiretaps were gathered as part of an investigation into how public-works contracts were awarded.

The purported conversations were between Angelo Balducci, who oversaw the Italian government's awarding of construction contracts -- including work on the airport at Perugia -- and Thomas Chinedu Ehiem, a 39-year-old Nigerian singer. They were recorded between April 14, 2008, and January 20, 2010.

In addition to working for the government, Balducci served as a "gentleman of his holiness," also known as a papal usher or "Vatican gentleman." The main responsibility of the ceremonial position is to welcome heads of state to the Vatican and escort them to see the Pope.

Balducci is one of three public officials who, along with a businessman, have been jailed on charges related to corruption in the public works department. The public officials are alleged to have awarded contracts to businessmen who offered them favors, money, sex, and/or house remodeling in exchange. The suspects, who deny the charges, are in "cautionary custody" though they have not been charged or indicted.

The Italian news media have nicknamed the scandal "grande opere," which translates as "big works." The transcripts of the wiretaps were made public on Wednesday and widely disseminated in the media.

Balducci's lawyer, Franco Coppi, lambasted investigators' handling of his client.

"It is shameful that things unrelated to the investigation are published," Coppi told reporters Wednesday outside the Rome prison where Balducci was confined. "We are thinking about taking legal action. During the interrogations, we did not discuss private matters."

Ehiem told the Italian weekly magazine Panorama in an interview published Friday that he provided Balducci with men from Italy and abroad, including rugby players, actors, models and seminarians.

Ehiem also told Panorama that he arranged for Balducci to meet escorts at Ehiem's house when the government official was in Rome and in Paris, France; Naples, Italy; and other cities when he was traveling.

"For Balducci, a 26- or 27-year-old man was too young," Ehiem told the magazine. "He preferred older men, above 40 years old."

According to the wiretap transcripts, in a conversation dated April 22, 2008, Ehiem says, "I called you ... because there are ... if you are free ... three or four situations that can be good ... very, very good ..."

Balducci: "...Hmmm!"

Ehiem: "Two black, Cuban men ... really tall, tall, tall ... so ... if you are free ... we can try to organize right away ... that is, I saw both of them, Angelo ... believe me that ... they could be two excellent options."

In another conversation, dated August 21, 2008, Ehiem says: "Look, if you want I can have them come one after the other ... it is possible ... if you have some free time ... I can arrange for the two of them."

Balducci: "Which are the better ones?"

Ehiem: "The better ones are the ones I just told you about ... one from Bologna and the other one from Rome."

Balducci: "All right, then let's do it for 3:30."

Ehiem: "OK."

Ehiem said an escort friend introduced him to the Italian businessman more than a decade ago. "He asked me to do it with him, but I like women and just the thought grossed me out," Ehiem said.

"He asked me if I could procure him other men. He told me that he was married and that it had to be done in great secrecy. I told him that there was the Internet. But he asked me to take care of it because he couldn't do it from his home."

He added, "Sometimes he would ask for two meetings a day."

Ehiem told Panorama he was trying to support his family in Nigeria, and that Balducci sometimes paid him 50 or 100 euros, but "never more than 1,000 to 1,500 per year."

Neither Balducci nor his attorney has commented on Eheim's interview with Panorama.

A Vatican source who asked not to be identified said Ehiem had been dismissed from his choir duties. Asked about Balducci, the source said, "It is obvious that, while in prison, he cannot exercise his duties as a papal gentleman." But, the source noted, Balducci has not been convicted of any charge.

"If he is convicted, then we will look into it," the source said.

CNN's Hada Messia contributed to this story from Rome.