Pietro Esposito went missing after being allowed day release from a jail in Pescara, in the Abruzzo region, on December 15th, Il Messaggero reported on Friday.
The mafia informant was involved in the 2004 torture and murder of 22-year-old Gelsomina Verde, the newspaper said.
As the search continues for Esposito, police are also hunting for serial killer Bartolomeo Gagliano, who went on the run in the north-west city of Genoa after being allowed out of prison to visit his mother.
Gagliano killed two prostitutes and a man between 1981 and 1989. He was found guilty of a number of other crimes including attempted murder and abduction, and was sent to a prison psychiatric ward for treatment.
But in 2002 prison authorities decided Gagliano was no longer a danger to society and allowed him to go free. He was rearrested in 2006 and jailed for robbery, damage to public buildings and attempted extortion.
On Friday the justice ministry defended the prison authorities’ decision to grant Gagliano day release from prison, prompting a manhunt after he failed to return earlier this week.
“Permission was granted on the basis of experts’ assessment; he is still a danger to society but we stress that this has been reduced thanks to a number of factors,” the justice ministry said in a statement.
Gagliano was no longer taking medication, demonstrated a high IQ and his behaviour had been praised by prison staff, the ministry said. He had already been granted leave in August and November, after which he returned to prison.
The justice ministry also said the prison staff knew of Gagliano’s murders, after the prison warden was quoted as saying he was unaware of the killer’s long criminal history.
But aware that a serial killer on the run “has aroused worry and alarm in public opinion”, the justice ministry said it would be carrying out a fact-finding investigation over Gagliano’s escape.
Last year, authorities granted day release 25,275 times, from which prisoners failed to return 52 times, the ministry said.