The car bomb shook Ranucci's house near Rome. The journalist and his daughter were home at the time, but no one was injured.
The businessman, who had been friends with Ranucci, was arrested earlier this week and has admitted to being behind the attack. In late June, Italian police arrested four men suspected of carrying out the attack on behalf of the businessman.
Sigfrido Ranucci is a well-known investigative television journalist who has investigated the mafia and political corruption in the country, among other things. He has had police protection for several years.
The businessman says, according to his lawyer, that he organized the bombing because he wanted to strengthen the journalist's personal protection.
