It was a shocking case of betrayal and furious retribution that resonated with horrified parents the world over.
In remote woodlands in deepest Russia, an enraged Vyacheslav Matrosov stood face-to-face with the one-time friend and babysitter he had caught abusing his six-year-old daughter.
Moments later, after a vicious knife-fight, 32-year-old Oleg Sviridov was dead – Matrosov having apparently succeeded in making the child sex attacker dig his own grave and then take his own life.
The extraordinary story of how a father confronted the abuser of his child instantly struck a chord with the public - even more so when Matrosov was arrested on suspicion of murder, which could have seen him face a lengthy spell in jail.
His arrest was accompanied by an outcry with villagers pitching together to fund his winding legal battle and declaring: 'Every father would have done this.'
Eventually, the 35-year-old was convicted of 'inciting a person to suicide or attempted suicide by threats or abuse' and served just six months of an 18-month sentence.
Oleg Sviridov (left) and Vyacheslav Matrosov (right) were friends before the discovery
Matrosov, 35, whose daughter was a victim of Svirdov, has been freed from jail early after just six months. Matrosov is pictured with his wife Natalya Matrosova and his two daughters
The body of Sviridov was found in a shallow grave he appeared to have dug himself
'Slava' Matrosov and Oleg Sviridov had been good friends before the deadly episode unfolded. Sviridov would often babysit Matrosov's children and the pair had for a long time been close and trusting friends.
Nobody could have suspected what was really going on. 'They left their children with him all the time,' Sviridov's mother would later comment. 'When he baby-sat these girls he came back home as normal, in a good mood.'
'He must have been drunk. Most likely he was drunk,' she said, trying to understand how her son could have become such a monster.
It was when the friends were drinking together that Matrosov uncovered the ugly truth. When Sviridov fell asleep, his friend took his phone to see what he had been looking at, it was later claimed in court documents.
To his horror he discovered a video of his best friend forcing his child to perform a sex act. The girl - who sources say was Sviridov's goddaughter - was allegedly heard in the video pleading: 'Oleg, that's enough, I can't take it any more. I want to go home'.
Police would later say that Sviridov's phone also contained sickening videos of the rapes of other girls from the village, aged six and 11. The videos indicated that the suspect had been abusing children for five years before Matrosov discovered the footage on his phone.
It was said that one of the alleged victims was also the daughter of his former partner. 'The woman had a daughter from her first marriage,' a friend later told Moskovsky Komsomolets newspaper. 'Now it has turned out he was abusing the child.'
'He was constantly seen with the girls, the daughter of his partner and Vyacheslav's older daughter, in the village. It never crossed anyone's mind what he was doing with children.'
Matrosov gave Sviridov an ultimatum to turn himself in, it was claimed. When he failed to do so, Matrosov said he went to the police and reported the attacks himself.
The police began a manhunt for the sex offender as he tried to flee, but Matrosov got to him first - ostensibly hoping to spook his old pal into going to police and doing the right thing.
Sviridov was last seen badly beaten on the day he disappeared in September 2021, according to a relative. A week later, his body was found in the makeshift grave near Vintai village.
The details of what happened in those woods may never be fully revealed. But investigators concluded Sviridov was made to dig his own grave before the two were swept up in a furious row.
Matrosov later told police he did not mean to kill his old friend, but says he 'stumbled on' a knife during the argument. Sviridov lunged at Matrosov with the blade but caught himself in the process, sustaining fatal wounds.
Forensic teams ultimately concluded that Sviridov took his own life during the fracas.
Matrosov waited before going to the police and handing in the phone as evidence. He told the police he had only meant to scare his friend and had given him the choice: hand yourself in or take your own life.
The body of Sviridov, 32, was found near Vintai village in a grave prosecutors believe he was forced to dig himself
Matrosov, 35, forced his former best friend to dig his own grave in the Samara region of Russia
Vyacheslav (Slava) Matrosov, here aged 34, pictured with his daughters
Authorities found Sviridov's corpse in an unmarked pit a week after Sviridov disappeared. They arrested Matrosov on suspicion of murder, for which he faced 15 years in Russian prison.
The suggestion at first sparked outcry among residents of local village, many pooling together to fund the aggrieved father's legal battle.
'Every father would have done this [killed someone they saw abusing their child]. This will be an example to everyone,' read a petition calling for his acquittal at the time.
'Therefore, we demand understanding from the executive branch, the Ministry of Internal Affairs and the Investigative Committee.'
In April 2022, Matrosov was finally convicted of 'inciting a person to suicide or attempted suicide by threats or abuse' by Krasnoglinsky Court in Samara, and sentenced to 18 months in a strict Russian penal colony. He served just six months of the sentence after being freed a year early.
It was a reasonably light sentence compared to the six-year maximum penalty under the charge. Lawyer Vera Podkolzina said at the time proving Sviridov's guilt with the video evidence was critical to getting a lenient sentence for Matrosov.
'It is difficult to say what punishment the father of the girl may face, but he has very powerful mitigating circumstances,' she said.
'If the crime is proven by video facts, then is the girl's father wrong?' said Anna Plekhanova, commenting on a petition.
'He saved our kids from potential paedophile abuse,' said another supporter.
Matrosov always denied murder and said he was 'pleased' that he would not face a charge of deliberately killing Sviridov. The court also removed the requirement for him to wear an electronic tag as he awaited trial.
'Of course, we understand that he could have received a far longer sentence. And 18 months is not much time,' said Oksana Kazakova, a Matrosov family friend and Sviridov's ex-girlfriend, whose daughter was also allegedly abused.
'We really hope that he will get a presidential pardon at the end of the year. That would be a huge blessing for all his friends and family.'
Still, the story triggered a wave of sympathy around Russia, making headlines around the world.
Prominent TV journalist and former Russian presidential candidate Ksenia Sobchak told her followers at the time: 'All parents are standing up for the paedophile's killer.'
Matrosov's father updated supporters with a message on a fundraiser.
'We have collected the money, thank you all,' he said. 'It was not friends or relatives who helped, but strangers from the village.'
Vyacheslav (Slava) Matrosov (right) is pictured with his wife, Natalya (left) and daughters
Former rocket engine factory worker Matrosov (pictured with wife Natalya) said he reported the rapes to the police but claimed to have tracked him down before the police could find him
Sviridov's body was found in the forest near the village of Vintai in the Samara region of Russia
Some 2,500 people signed a petition demanding that Matrosov be fully acquitted, with locals in the village of Pribrezhnaya even pitching in to pool money for his legal fees.
Matrosov was finally reunited with his family in October last year after six months in jail.
'Home,' he said in a post shared online, sat next to his wife Natalya, then 35. 'Love very much.'