The explosion, which occurred in the town of Pomezia about 20 km (12 miles) south of Rome, destroyed two vehicles belonging to Ranucci, a prominent investigative reporter known for exposing corruption and organized crime. No injuries were reported in the attack.

In a statement, the Carabinieri said the four suspects, detained near Naples, were strongly suspected of possessing, transporting and using explosive devices in a public place, issuing threats and causing damage under aggravating circumstances linked to acting as part of a group using mafia-style methods.

Three of the suspects were placed in pre-trial detention, while a fourth was ordered under house arrest, police said.

Ranucci, host of the investigative television programme “Report” on public broadcaster Rai 3, has lived under police protection for several years because of repeated death threats linked to his reporting.

Speaking to Italy’s ANSA news agency following the bombing, Ranucci said he had received “an endless list of threats.”

The investigation, led by the Rome Anti-Mafia Prosecutor’s Office, involved extensive analysis of surveillance camera footage, telephone records and forensic examinations of the explosive device, according to the Carabinieri.

Investigators believe the individuals who carried out the bombing acted on behalf of unidentified third parties who allegedly organized logistical support, including financial assistance, dedicated mobile phone cards, legal support and contingency plans to facilitate the suspects’ escape abroad if necessary.

Authorities said efforts to identify those believed to have ordered the attack remain ongoing.

The first U.S.-born pontiff traveled to Acerra, near Naples, where he urged people to reject “temptations of power and enrichment” linked to activities that damage the environment and communities. The visit came as the Vatican prepares to publish Leo’s first encyclical on Monday, a major teaching document expected to address artificial intelligence, warfare and workers’ rights.

Speaking before residents affected by decades of pollution, Leo said he had come to the region to “gather the tears” of families who had lost loved ones to illnesses linked to toxic waste contamination. He criticized what he described as the failure to curb environmental abuses and said those responsible had been allowed to act without accountability for too long.

Crowds gathered in Acerra’s main square to welcome the pope, waving Vatican flags and displaying photographs of relatives who had died. During his four-hour visit, Leo met with victims and reiterated concerns about what he called the “dizzying profits” earned by a small number of actors at the expense of public health, employment and future generations.

The area around Naples, commonly known as the “Land of Fires,” has for decades been associated with illegal dumping and burning of industrial waste. Waste management operations in parts of southern Italy were historically linked to private contractors, some of whom were alleged to have connections with the Camorra, the Naples-based organized crime network.

In January 2025, the European Court of Human Rights ruled that Italian authorities had failed for years to adequately protect residents from the consequences of illegal waste disposal in the region, citing shortcomings dating back at least to 1988.

The court ordered Italy to develop a comprehensive database of contaminated sites and improve public communication about health and environmental risks.
Following the ruling, Prime Minister Giorgia Meloni appointed a senior military official in February 2025 to lead a task force focused on environmental remediation efforts and assistance for affected communities.

Leo has increasingly adopted a more direct tone on social and environmental issues in recent months. His latest intervention places environmental protection and corporate accountability at the center of his public agenda ahead of the release of his first major papal document.