A Brazilian man arrested for stabbing a woman to death calmly confessed to murdering another 41 people - putting him among history's most prolific serial killers, it was reported today.

Sailson Jose das Gracas, 26, told police in Rio de Janeiro he would go out 'on the hunt' for white women after studying each victims for up to a month.

In an unreported reign of terror spanning nine years, Gracas claims to have murdered 37 women, two men and one two-year-old child in the outlying area of Rio de Janeiro known as Baixada Fluminense.

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Sailson Jose das Gracas, 26, told police in Rio de Janeiro he would go out 'on the hunt' for white women after studying each victims for up to a month

He told police: 'I would watch the victim, study her. I would wait a month, sometimes a week, depending on the place. I would get to know where she lived, how her family were, if she passed by on the street, I would watch, have a look at her house, studying her.

'In the early hours of the morning, I'd get through a gap in her house, really easily, and take advantage.'

In an interview in front of TV cameras at the police station in Nova Iguacu, Garcas said he found pleasure in seeing the life drain out of the women he murdered.

He said: 'I would stop in the bakery, or in a square, reading a newspaper. I would look at a woman and say to myself, "it's that one".

'I would follow her to her house, but I never raped anyone. Women for me has to be white, not black, because of my colour. '

I got pleasure from them fighting, screaming and scratching me. I thought that I was crazy, sometimes normal.'

Chillingly, Garcas admitted he had become 'addicted' to murder.

In an unreported reign of terror spanning nine years, Gracas claims to have murdered 37 women, two men and one two-year-old child in the outlying area of Rio de Janeiro (pictured) known as Baixada Fluminense

'The first woman I killed I strangled with my hands. I felt pleasure, I liked it. I felt a very strong desire. I've already killed 38 women, I'm addicted,' he said.

He also told camera he was eleven when he lost his father, who was electrocuted during an accident at work.

He said: 'It marked me a lot. But that wasn't the reason why I committed these crimes.'

Marcelo Machado, the Rio police chief investigating the supposed serial killer, said Sailson found pleasure in stragulating his victims, and masturbated after his murders.

WORLD'S MOST PROLIFIC SERIAL KILLERS Amelia Dyer - known as 'The Baby Butcher' Killed 200 children in the 1800s in Bristol, UK Luis Garavito - known as 'The Beast' Confessed to 140 child murders in Colombia in the 1990s, but may have killed as many as 400 Pedro Lopez - known as 'The Monster of the Andes' Between 1969 and 1980 in Colombia, Ecuador and Peru he killed 110 young girls. He was released from jail in 1998. No one knows where he is. Daniel Camargo He confessed to killing 72 people in Colombia and Ecuador between 1974 and 1986. Pedro Rodrigues Filho Between 1967 and 2003 this Brazilian murdered 71 people and was sentenced to 128 years. Forty seven of his victims were inmates Kampatimar Shankariya He murdered at least 70 with a hammer in India between 1977 and 1978 Yang Xinhai Chinaman Xinhai used axes, meat cleavers and hammers to butcher 67 people between 2000 and 2003 Abul Djabar He used turbans to strangle 65 men and boys up in 1970 and the years leading up to it in Afghanistan Andrei Chikatilo Known as the Butcher of Rostov, he murdered 53 between 1978 and 1990. Anatoly Onoprienko Known as the Beast of Ukraine, between 1989 and 1996 he murdered 52. Source: Wikipedia Advertisement

He said: 'On occasions, he killed his victims and masturbated on seeing them with their eyes open.'

Police chief Pedro Henrique Medina, from the Baixada Fluminense Homicide Division, said Gracas voluntarily confessed to the murders have being caught in the act of murdering his latest victim.

He said he believed his testimony because only the author of the crimes could recall them in so much detail.

He said: 'His desire to kill was for women, and he didn't kill black women, just white. He followed the victim, studied her step by step until he managed to commit the crime.'

Gracas was arrested after stabbing to death a 26-year-old woman identified as Fatima Miranda, in her home in the town of Nova Iguaçu, Greater Rio de Janeiro.

During the investigation into her death, police officers arrested Gracas and two other people, Cleusa Blabina and Jose Messias, who were with Ms Miranda on the night of her death.

The three were arrested after giving contradictory versions of what happened when questioned by police.

After they were taken to the police station, Gracas admitted that he had been paid by the other two accomplices to murder Ms Miranda.

He also admitted killing two men for money, and then detailed the dozens of other women he had murdered for his own pleasure in his serial killing spree.

Gracas claimed commiting murder would help him 'calm down'.

He said: 'When I didn't do it, I'd become nervous, I'd pace up and down inside the house. And when I'd done it I'd become calmer. I'd do a victim, and I could stay two months without doing it, or three. I'd stay fine, I'd just be thinking of that one that I'd killed. Then I'd go out on the hunt.

'I didn't kill worrying about going to jail. I did everything well, it's because I really like it doing it. I was most concerned with fingerprints, or if the place had a camera. I wouldn't take any documents with me so I wouldn't leave any clues for the police.'

During his testimony Gracas also confessed to killing a two-year-old child because he was afraid her cries might wake up neighbours after he had killed her mother. He said his taste for murder began as a teenager.

He said: 'I started to steal small things, do small robberies. And as I grew up I started having other thoughts. My thinking started to change, understand? From robbing, I started to think about killing. Aged 15, I stole handbags. After that, aged 17, I killed the first person.

'It gave me that adreneline rush, the first woman. And I thought about jail. Will I get caught? The things flowed well. So I started thinking about doing it more and more. And I liked it and started to get used to it.'

Chillingly, Gracas claimed he did not regret any of the murders.

Tiago Henrique Gomes da Rocha, another Brazilian, confessed to murdering at least 39 people in just three years

He said: 'I have no regrets, no. For me what I did is done. I wouldn't change anything, I don't regret anything. If I leave prison in 10, 15 or 20 years, I'll start doing the same thing again. It's my will, there's no other way. I leave, choose my 'women', the women I like to choose, and if I think that it has to be, it will.'

According to police records, Sailson was arrested twice in 2007 for robbery and theft, carrying illegal firearms in February 2010 and theft again in February this year. But his murders remained undiscovered until today.

Police have now launched an investigation into Gracas' claims and are calling on families of murder victims over the last nine years to get in touch.

Rocha began killing in 2011, at first targeting homeless people, gays and prostitutes

Gracas spent last night in a police cell and will be transferred to a maximum security jail in Rio de Janeiro today.

His arrest comes after Tiago Henrique Gomes da Rocha, another Brazilian, confessed to murdering at least 39 people in just three years

Rocha, 26, was arrested in October after being pulled over in the city of Goiania, when local police found he was facing trial for stealing a motorcycle's license plate in January.

He was stopped while riding with fake plates on the motorcycle he often used during the murders, when he would drive by and attack random victims before speeding away.

A day later, he confessed to killing 39 people — 15 young women as well as prostitutes and random people he thought to be gay or homeless.

In a sick twist, it has been revealed that Rocha was in a romantic relationship with a pretty church girl with long hair, her appearance similar to that of his victims, the newspaper Folha de S. Paulo reported.

Rocha began killing in 2011, at first targeting homeless people, gays and prostitutes. His first victim was a man, the first of 17 males he would eventually kill.

This year, he turned his attention to young women.

The list of the 15 most prolific modern serial killers is topped by Colombian Luis Garavito, a child murderer and rapist known as 'La Bestia' or 'The Beast.' He is thought to have killed more than 400 people, mostly street children. His proven victim count is 138.

Pedro Rodrigues Filho, Brazil's most prolific killer, claimed to have killed more than 100 victims, 47 of them inmates. He was convicted of killing 71 people.