Kaspars Petrovs was born in 1978 in Grobiņa, in western Latvia, the son of a prominent doctor, and by the time of the killings had been living homeless on the streets of Riga for about three years. He had a conviction for theft from 1998.
Between 2000 and 2003 he followed elderly women home in Riga and got into their apartments, either by force or by presenting himself as a technician from Latvijas Gaze, the state gas company. Once inside he strangled them and took what was there. The total taken across the series was put at about eighteen thousand lats, then roughly twenty-six thousand euros.
He was arrested on February 3, 2003, initially in connection with five deaths, and went on to admit more than thirty. The prosecution charged him with thirty-eight murders and eight attempted murders along with a string of thefts and robberies.
The court convicted him of thirteen. Doubt about what he had done was not the reason. At many of the scenes there had been no sign of a struggle, the deaths of elderly women had been recorded as natural, and the bodies had been buried without an autopsy, so there was no forensic evidence left to bring. The prosecution spokeswoman, Dzintra Vitolina, said murder could be proved in only thirteen of the cases. Besides the murders he was convicted of robbery and of inflicting serious bodily injury. At least one Baltic report of the verdict described him as sentenced for all thirty-eight; the court's conviction was for thirteen.
His own account at trial was that he had not meant to kill. He said, "I wanted only to rob them, not to kill them," and that he strangled the women only to make them lose consciousness so that he could rob them, and that they were often still breathing when he left. He also blamed what his family had expected of him: he said he understood he would never earn what was demanded of him, and so turned to crime. After conviction he apologized to the victims' families in court and asked their forgiveness.
The Riga Regional Court sentenced him to life imprisonment on May 12, 2005, at twenty-seven. "I cannot return the victims to life by words," he told the families, "but I wish they were still alive, that nothing had happened and that I wasn't here." He is described as the most prolific serial killer in modern Latvian history.