Clinging to his son’s coffin, Vincenzo Agostino solemnly swore that he would not cut his hair or beard until justice was served. It was 10 August 1989, five days after two mafia hitmen on a motorbike had killed Antonino Agostino, a police officer, and his wife, Ida, who was five months pregnant.

The couple were shot dead in broad daylight on the seafront promenade in Villagrazia di Carini, a town about 20 miles from Palermo. Vincenzo witnessed his son’s agony as the killers fired a full magazine of bullets at him. He saw his daughter-in-law, who was shot in the heart, move closer to her husband in a vain attempt to console him.

Last month a judge released a report revealing how Antonino Agostino was murdered because he was investigating fugitive mobsters. One of the killers, the mafia boss Nino Madonia, was sentenced to life in prison in March. It was a small step forward, despite many unanswered questions and the fact that many of those involved in the murder are still at large.

Martino Ceravolo by the grave of his son, Filippo Ceravolo, who was killed in 2012. ‘I’ll continue to knock on my son’s grave to let him know I haven’t given up,’ he says. Photograph: Alessio Mamo/The Guardian

The sentence has reignited debate in Italy over the sluggish legal process and agonising struggle for judicial closure for family members of innocent victims of the mafia.

Thirty-two years later, Vincenzo has kept his promise: his long beard now reaches his chest and has become a symbol of resistance against mafia bosses and for the long quest for the truth facing hundreds of relatives of victims of organised crime in Italy.

According to a report from the anti-mafia association Libera, almost 80% of about 600 cases of innocent victims of organised crime in Italy have been only partially solved or are completely unsolved. Most investigations have been closed for lack of evidence, while many others are trapped in endless trials and dozens are awaiting judicial action.

The distress and frustration that the victims’ relatives carry with them cause a range of psychological problems, such as depression, panic attacks, suicidal thoughts and post-traumatic stress. The Guardian travelled to four regions in southern Italy with a history of organised crime, interviewing parents and children of mafia victims who, decades after the murder of their loved one, are demanding that the cases be reopened.

For more than 30 years, Vincenzo Agostino has pursued prosecutors relentlessly to convince them to reopen the investigation into his son’s death, which has been closed dozens of times. During an earlier investigation, it was revealed that during the violent war the mafia waged against the Italian state in those years, Antonino was working as a secret agent charged with locating fugitive mafiosi. His death uncovered the alleged relationship between members of the Italian secret service and mafia bosses, which continues to be a focus of investigations today.

“Today, one thing is clear: some notable member of the state betrayed my son Antonino and informed the mafia of his role as a secret agent,” says Vincenzo. “Who are the faithless and deceitful institutional representatives who betrayed this country and served a death sentence to members of the police and magistrature? No, it is still not time to cut my beard.”

In a police lineup in 2016, Vincenzo picked out a colleague of his son who was implicated in the murder. For this reason, at 86, he is forced to live under police protection 24 hours a day.

“Watching your son, daughter-in-law and unborn grandson die destroys your life. I carry in my heart a wound the size of a crater,” Vincenzo says. He and his wife, Augusta, led the battle to uncover their son’s killers. Augusta died in 2019. On her gravestone, next to her son in the Santa Maria di Gesù cemetery in Palermo, is inscribed: “Here lies Augusta, mother of Antonino, who still awaits truth and justice.”

Vincenzo Agostino vowed not to cut his beard until he had achieved justice. ‘It is still not time,’ he says. Photograph: Alessio Mamo/The Guardian

In another cemetery, about 200 miles away in the territory of the Calabrian ’Ndrangheta, another father knocks on his son’s gravestone. He asks if he can hear him and wants to know what it’s like up there in heaven. The father’s name is Martino Ceravolo, and he says has not known peace since the ’Ndrangheta killed his son Filippo, 19, by mistake on 25 October 2012 near Soriano Calabro.

“That evening, Filippo had planned to visit his girlfriend, who lived in a small town four kilometres from here,” says Martino, 52, who ran a confectionery stand with his son. “His car wasn’t working, so he tried to hitch a lift. A young man from Soriano Calabro offered to take him there. Unfortunately, he ended up in the wrong car on the wrong night.”

At that time, a violent war was raging within the ’Ndrangheta between the powerful Emanuele clan and the Loiero clan. Filippo could not have known that Domenico Tassone, who had offered him a lift, was on the rival clan’s hitlist. At about 10pm, four men surrounded Tassone’s car and started shooting. Bullets meant for Tassone hit Filippo in the head and chest.

“When I arrived at the scene of the crime, my entire world fell apart,” says Martino, who takes tranquillisers every day to cope with his panic attacks. “Tassone left the car screaming, ‘they wanted to kill me!’ He miraculously survived, as Filippo lay on the ground in a pool of blood.”

Filippo’s case was closed for lack of evidence, despite prosecutors having identified the four men responsible for the attack, who continue to control the local area. “Those criminals took my son’s life – and ours, too,” says Martino.

Angelina Landa with a photo of her father, Michele Landa, who was murdered by the Camorra in 2006. Photograph: Alessio Mamo/The Guardian

One of Martino’s daughters suffers from depression, and his wife tried to kill herself three years ago after her son’s case was closed yet again.

“We’ve been abandoned without any psychological support,” says Martino. “I, too, have thought of taking my life. I’ve thought of setting myself on fire in front of the ministry of justice.”

The psychological impact on families can be devastating, especially in the case of “ambiguous loss”, in which the bodies of victims are never recovered. Close family members living in a constant limbo can develop serious depression or alcoholism.

“After the death of my father, I suffered from anxiety and panic attacks for years, while my mother dealt with depression for the rest of her life,” says Daniela Marcone, 52, vice-president of Libera.

Daniela Marcone, with a photo of her father, Francesco Marcone, who was murdered by the mafia in 1995 in Foggia. Today she is a leader of the anti-mafia organisation Libera. Photograph: Alessio Mamo/The Guardian

Daniela’s father, Francesco, was gunned down on the evening of 31 March 1995 in the stairwell of his apartment building, by a killer from the local mafia in Foggia, Puglia. He was the director of the public tax agency, who had denounced corruption in his office and tax evasion by several firms.

Despite the fact that Marcone’s murder was a textbook mafia killing, his case remains unsolved. “I know of mothers who have reached out to mafia bosses, pleading with them to reveal the location of the body, just to be able to give their child an honourable burial.”

The wait for justice can become so frustrating that many victims’ relatives have become pseudo-detectives. When Angelina Landa understood that the police were not investigating the death of her father, Michele, a 62-year-old security guard allegedly killed by the Neapolitan Camorra, she decided to take matters into her own hands.

In 2006, the Casalesi clan of the Camorra mafia, which inspired the TV series Gomorrah, had turned to the lucrative business of stealing industrial telephone batteries. Michele had been assigned to guard a Vodafone relay station near Mondragone, in Campania, which was controlled by the Camorra. His charred body was found on 5 September 2006 inside his little Fiat.

“My brothers and I agreed that we had to act soon,” says Angelina, 48, a primary school teacher. “Five days after his disappearance, we jumped over the fence where the police had moved his burnt car. Among the ashes we found his bones. After five days, they still hadn’t removed his remains from the car.”

Investigators closed the case after a few months, citing lack of evidence.

Another compounding factor in the resolution of cases is omertà, the mafia’s code of silence. “Mafiosi rarely testify against their own, including their rivals,” says Marcone.

“In a mafia killing, it’s difficult to find witnesses among ordinary people, especially in small towns where organised crime groups are deeply embedded and omertà is a social phenomenon,” she says. “People are reluctant to come forward because they fear the bosses’ reprisals.”

“The code of silence is the basis of the mafia’s strength,” says Federico Cafiero De Raho, national anti-mafia prosecutor. “Investigations into mafia killings can be really complicated. A murder ordered by bosses never has just one perpetrator, but a chain of those responsible. This makes the investigation difficult, unless an arrested mobster decides to speak out.”

Paradoxically, sometimes the hope of reopening mafia cases lies in the hands of the same people who committed those murders: mafiosi who are arrested and decide to collaborate with prosecutors in exchange for reduced sentences. In recent years, such cases have shed light on numerous “cold cases”.

“I thumb through the paper every day in the hope of finding news of a recent mafia turncoat,” says Marcone. “I realise it’s frustrating, but I’ve never sought a vendetta, only justice. And until I find it, I’ll continue to knock on my son’s grave to let him know I haven’t given up.

“Without justice, there is no peace,” he says. “Not for me, nor for him.”