( CNN ) A Brazilian man has confessed to killing 39 women in the Rio de Janeiro region , police said Thursday -- shocking claims that , if confirmed , would make him one of the most prolific serial killers in the country 's history . In an interview with Brazilian broadcaster TV Globo , the alleged killer , Sailson Jose das Gracas , said that he carried out the first slaying when he was 17 and continued to kill over the next decade . `` I started robbing purses and small things like that , '' he told TV Globo . `` And as I got older , I started having a different thoughts . My thoughts started changing . From stealing , I started thinking about killing . '' Sailson , reported to be 26-years-old , said he did n't kill impulsively but stalked his victims . Rio police said they arrested Sailson on Wednesday on suspicion of killing a woman in the suburb of Nova Iguacu . He confessed to that homicide and then told police about the other killings , they said . Sailson described his need to kill as pathological . `` When I did n't kill , I would get nervous , '' he told TV Globo . `` I would pace around the house , and then when I killed , it calmed me . '' Police chief Marcelo Machado told TV Globo that Sailson is also suspected of killing a 2-year-old boy , the son of one of the dead women . Fast Facts on serial killers . 'No regrets ' Specialized police teams are carrying out an investigation into his claims . `` We must carefully examine , one by one , '' Machado said . Police said they had located four other cases from the homicide division that had the same modus operandi presented by Sailson , who told them he used knives to kill . Police said they had also arrested a man and woman , who Sailson said had told him to kill the latest victim . The self-declared killer said he had `` no regrets '' about his actions and would kill again if set free . `` What is done is done , '' he told the TV network . `` If I leave here in 10 , 15 , 20 years , I 'll go back to doing the same thing . '' Opinion : A surprising truth about serial killings .
Police : A man arrested on suspicion of a killing confesses to dozens more . Sailson Jose das Gracas tells a TV station that he 's been killing for a decade . `` When I did n't kill , I would get nervous , '' he says . Rio de Janeiro police say they have set up special teams to investigate the claims .