Mikhail Popkov, 54, sits inside the defendants' cage as he is convicted of 56 new murders in Irkutsk, Siberia

Russia's worst-ever serial killer nicknamed 'The Werewolf' has today been convicted of carrying out 56 more murders.

The latest convictions mean former policeman Mikhail Popkov is guilty of slaughtering at least 78 women after an earlier guilty verdict.

He was sentenced to life, meaning he will die in a harsh penal colony.

But in an extraordinary dispute after today's court ruling in Irkutsk, Russia's state prosecutor and the country's 'FBI' - the Investigative Committee - openly disagreed on whether the true overall victims' total should be 78 or 81.

Popkov, 54, claimed he wanted to clean up his home city of Angarsk in Siberia of 'prostitutes' and 'immoral women'.

He raped most of his victims before butchering them with knives, axes or screwdrivers.

A Russian state prosecutor said today: 'He clearly loved killing. Some victims had 145, or even 170 knife wounds.

'He said that he felt satisfied when he felt their pain as they were stabbed.'

The cases go back to 1992, just after the collapse of the Soviet Union, with the most recent in 2010.

Mikhail Popkov, 54, uses a prop to provide evidence of how he hacked one of his victims to pieces in the Siberian wilderness

The killer, known as 'the werewolf', was sentenced to life meaning he will die inside a brutal Russian prison

Mikhail Popkov, a former policeman, poses for a photograph with cross-country skis while enjoying his double life as a family man

His victims were aged from 18 to 50, said law enforcement sources.

Popkov - also known as the Angarsk Maniac - reacted with anger in his courtroom cage today after he was stripped of his junior police lieutenant rank, which means that he will not receive his £285 a month state pension.

'He was calm when he heard the life sentence, but then got very upset about the rank and pension decision,' said state prosecutor Alexander Shkinyov.

'Popkov thought that his co-operation with investigation should have earned him a better result from the court.

'He will be appealing this part of the sentence (to remove his pension).

The skeletal remains of one of Popkov's female victims lies on a tarpaulin after being recovered for evidence

Popkov with his wife Elena; officially, he remains married to her and she was unaware of his double life as a mass killer

The killer, also known as the Angarsk Maniac, was furious in his iron cage after he was stripped of his junior police lieutenant rank, which means that he will not receive his £285 a month state pension

The wife of Popkov was unaware of her husband's sickening murders while they lived together

'This sentence covers the criminal case where we proved 56 murders plus one murder attempt.'

He had been convicted of 22 murders of women in 2015 - for which he was also sentenced to life - and since then has cooperated with police in identifying other victims.

He had confessed to 60 new murders - and the court found evidence for 56.

'We found skeletons of 12 women that were announced as missing,' said Shkinyov, reported The Siberian Times.

'Among the victims there were women aged from 18 to 50.

'He said he 'sentenced them to death' as soon as they agreed to share a drink with him' - because to him this proved they were immoral.

He forgave three women because they didn't agree to drink with him. HYe escorted these women home and even helped some of them to carry their bags.

'He clearly loved killing. Some victims had 145, or even 170 knife wounds. He said that he felt satisfied when he felt their pain as they were stabbed.'

It is unclear where Popkov will service his life sentence but it will be one of Russia's harsh high security jails, almost certainly in Siberia.

His victims were aged 18 to 50 and prosecutors said he 'clearly loved killing', stabbing his victims up to 175 times

The werewolf stands in handcuffs as he cooperates with police in indicating the locations of his crimes

The sentence means he will die in jail.

'I don't know for sure where he serve his sentence, but it'll have to be jail for lifers, so something like Harp or Polar Owl, and in solitary confinement.

'There is nothing stricter than the sentence he received because Russia does not allow the death penalty.'

The state investigator Yevgeny Karchevsky who made the key breakthrough in securing Popkov's confessions said more victims may yet be found.

'Popkov is a very cruel man,' he said. 'If to describe him in one word, he is a hunter.

'He was looking for prey, he was killing the prey, receiving energy and satisfaction from it, and lived with this amount of energy until his next murder.

Popkov and his wife had a daughter, Ekaterina (right, with her father), who spoke of her difficulty in believing her 'loving father' was a bloodthirsty killer and rapist

Popkov was highly convincing in leading a double life; able to raise a daughter with his wife and working hard as a policeman, all the while committing vile atrocities

'I cannot say that we found have everyone (he killed).

'During our last meeting I asked Mikhail: 'With this, are we closing it all? He did not say "YES".

'He said: 'I told you everything I can remember.'

In an extraordinary dispute over the number of victims, the Investigative Committee claimed his new total - for which he was formally convicted today after an earlier confession - was 59.

Officially, he remains married to his wife Elena who was unaware of his double life as a mass killer.

She has moved to another city and changed her identity.

The couple have a daughter Katya, a teacher, who has married since his first conviction.

Mikhail Popkov told investigators he would ask women for a drink and if they wanted one he deemed them immoral and would murder them

She also spoke of her difficulty in believing her 'loving father' was a bloodthirsty killer and rapist.

She said: 'Watch how a butcher works, he is covered in blood from head to toe.

'Did the women lay down meekly by themselves?

'I bet they would leave marks - bites or scratches. You cannot hide this.

'But my father did not have any suspicious marks on his body or face.'

In leaked testimony Popkov confessed: 'I had a double-life.

Popkov hangs his head as the verdict is read out on Monday

'In one life I was an ordinary person, I was in the service in the police, having positive feedback on my work.

'I had a family. My wife and daughter considered me a good husband and father, which corresponded to reality.

'In my other life I committed murders, which I carefully concealed from everyone, realising that this was a criminal offence.

'My wife and daughter never knew about the crimes I committed and did not even suspect this.'

He coldly revealed how he cruelly selected women to kill during his 18 year reign of terror in Irkutsk region between 1992 and 2010.

'The victims were those who, unaccompanied by men, at night, without a certain purpose, were on the streets, behaving carelessly, who were not afraid to enter into conversation with me, get into my car, and then go for a drive in search of adventures, for the sake of entertainment, ready to drink alcohol and have sexual intercourse with me.'

He used his police car, offering lifts to some victims, then taking them to remote areas to rape and murder them.

A prison guard stands and watches Popkov as the verdict on Monday brought his macabre tally to 78

The Siberian policeman offered his victims late-night rides and would hack them to pieces after raping them

Investigator Yevgeny Karchevskiy in court; he was key to Popkov's agreement to divulge the details of his crimes

Investigators never believed a policeman could be responsible for such crimes.

'Not all women became victims, but those of a certain negative behaviour, I had a desire to teach and punish,' he said of his decision who would live and die.

'Others did not behave in such a way, they were afraid ...

'The exception was the murder of (victim) Elena Dorogova, who was hurrying to the [railway] station to meet her mother. On this occasion, the woman was sober.'

He used the police station's store of weapons confiscated from criminals to use for his own murders, he admitted in testimony to criminal investigators.

'I had the opportunity then to take them,' he said.

'Then I threw them away either at the crime scene or nearby, wiping them with something to remove my fingerprints. The choice of weapons for killing was always casual.

'I never prepared beforehand to commit a murder, I could use any object that was in the car - a knife, an axe, a bat.

'I never used rope for strangulation, and I did not have a firearm either. I did not cut out the hearts of the victims.'

On one occasion he murdered a teacher at his daughter Katya's music school, he said.

'Her corpse was found in the forest along with the body of another woman,' he said.

'My daughter asked me to give her money, because the school was collecting to organise funerals. I gave her.'

He returned to one of his murder scenes after forgetting his police ID token at the scene and realising one of the victims was still breathing he pummelled her with a shovel

The killer told authorities in 2012, when he was first hauled in, that he acted on his moral convictions in killing prostitutes who partied 'as if it was the last day on earth'

The investigative team in Irkutsk, Siberia, that managed to uncover the crimes of Mikhail Popkov

Once he went back to the crime scene after leaving two women for dead, because he realised he had lost a police identity token at the site, which would identify him as the serial killer.

'I found the token right away, but saw that one of the women was still breathing,' he said.

'I was again shocked by the fact that she was still alive. I finished her with a shovel.'

These victims in the year 2000 were Maria Lyzhina, 35 and Liliya Pashkovskaya, 37.

The killer was judged mentally fit to stand trial.

He told the court: 'I admit my guilt in full....

'Committing the murders, I was guided by my inner convictions.'

After he was detained in 2012, he told police he wanted to 'cleanse' the streets of 'prostitutes'.

'They abandoned their husbands and children at home and went out to party as if it was the last day on earth,' he said.