Viewers protest after news of missing 15-year-old Sarah Scazzi and uncle's confession is relayed on air to relatives

Italians are debating broadcasting sensibilities after 3.5 million people saw a mother being told on a live show that her daughter had been murdered – and that her brother-in-law had confessed to the killing.

Concetta Serrano, the mother of 15-year-old Sarah Scazzi, who went missing in August, was taking part in Chi l'ha visto, a programme on the state-run RAI network that investigates disappearances. A news agency report reached the studio that investigators were searching for a corpse.

The presenter read the report to Serrano and other relatives, linked to the programme from her brother-in-law's house in the southern town of Avetrana. Further reports were relayed as Serrano sat expressionless, apparently in deep shock.

It was not until almost eight minutes later, after passing on the news that the owner of the house they were in was the suspected murderer, that the presenter, Federica Sciarelli, asked Serrano if she would like her to stop the programme.

The reply was: "It is better." But the broadcast continued for another three minutes, by which time a reporter standing behind Serrano was describing how, off-camera, the alleged killer's daughter was sobbing and protesting her father's innocence. "Ah. Obviously," responded Sciarelli before calling a commercial break.

A YouTube extract elicited a stream of protests. Viewers said they were disgusted, speechless and appalled. One wrote: "If you're a human being with the least heart, you can't do something like this."

Several defended Sciarelli, including one, Claudietto, who wrote: "The mother was on a TV programme. News came in and the journalist read it. It's her job for Christ's sake." Miticacal asked: "How is it the investigators told the press first and then the mother?"

The channel controller, Paolo Ruffini, said: "The programme tried to manage a very tragic affair in the most delicate possible way and I have to say the presenter achieved it."