Giuseppe Salvatore Riina (L), the son of the most feared Sicilian Mafia boss, leaves a prison in Sulmona, central Italy, in a February 28, 2008 file photo. REUTERS/Claudio Lattanzio/Files

By Steve Scherer

ROME (Reuters) - A convicted mobster whose father was the bloodiest of all Sicilian mafia bosses has sparked outrage in Italy by giving an interview to RAI state television in which he described his childhood as "nice" and refused to denounce the mob.

Giuseppe Salvatore Riina has written a book called "Riina Family Life" about growing up as the son of Italy's most wanted man, Salvatore "Toto" Riina, and appeared late on Wednesday on RAI's premier talkshow to promote his memoirs.

Not once during the interview did Riina, one of four children, criticize his father, and he refused to acknowledge the existence of the mafia, saying cryptically when asked to define it: "It could be everything or it could be nothing".

Italian politicians denounced RAI for allowing the interview to be aired and RAI's top managers have been summoned to appear before parliament's anti-mafia committee on Thursday.

Riina's 85-year-old father, nicknamed "the Beast", was arrested in 1993 and is serving multiple life sentences for murder, including for ordering the 1992 assassinations of anti-mafia magistrates Giovanni Falconi and Paolo Borsellino.

Investigators estimate that more than 1,000 people were killed in a mafia war in the early 1980s in which the elder Riina emerged as the supreme leader of Cosa Nostra.

His son was also subsequently convicted of mafia membership and sentenced to nearly nine years in prison. He is currently on parole.

During the half-hour pre-recorded interview, Riina said he had been home schooled and that he lied about his identity as a child to protect his father, who lived under an assumed name and told neighbors he worked as a surveyor.

Wearing a gray jacket and a white shirt, Riina did not flinch when shown scenes of the aftermath of the bombs that killed Falcone and Borsellino. He said his childhood had been a happy one, and the unusual circumstances had united his family.

"We shared a secret to keep the family together," he said. "We were unusual children and our lives were completely different from others, but it was also very nice."

Pietro Grasso, president of the Senate and Italy's former chief anti-mafia prosecutor, denounced the interview. "I don't care if Riina's hands caressed his children. They are the same hands covered in the blood of innocents," he wrote on Facebook.

Veteran talk-show host Bruno Vespa defended his decision to air the interview, saying "it's the first time we see how an important mafia family works".

Ferdinando Dome was aged 10 in 1969 when his father Giovanni, an innocent bystander, was gunned down in Palermo in a mafia shootout in which five people were killed. Riina was convicted of ordering the hit, known as the "Lazio Street Massacre", and given a life sentence.

"He said he had a great life with his father. My childhood was not so happy," Dome, the eldest of Giovanni's five sons, told Reuters.

"It bothers me very much that by broadcasting this interview on state television they are helping him sell his book."

(Reporting by Steve Scherer; Editing by Crispian Balmer and Catherine Evans)