Christenson was born in 1945 in Bethesda, Maryland, and had felony convictions from his teens. He moved between Canada and the United States. American reporting of the case reached for the comparison and called him a real American Jack the Ripper.
In 1981, in Montreal, he killed Sylvie Trudel, twenty-seven, and Murielle Guay, twenty-six. Both were decapitated and dismembered, and parts of the bodies were left in different places in the city; the Quebec press called the unknown killer the decapitator. In 1982, in Pennsylvania, he killed Michelle Angiers and Jeffrey Schrader, fifty-one, the latter after a fight in a bar.
He was arrested in 1982 and convicted in Pennsylvania in 1983, receiving life imprisonment without parole. The Montreal killings were not separately prosecuted, Canada not having sought extradition against a man already serving life without parole.
The higher figure reflects further attributions. Because only the Pennsylvania cases went to trial, the account of the Montreal killings rests on the investigation and on his own statements rather than on any judgment.