"You served as prosecutor, judge, jury, and executioner," US District Judge Richard J. Arcara told Kopp during the sentencing, the Buffalo News reports. "You decided that you know better than any law."
In October 1998, Kopp, known as "Atomic Dog" in anti-abortion extremist circles, hid in the woods outside of Dr. Slepian's house, shooting and killing Dr. Slepian through his kitchen window. Before his arrest by authorities in 2001, Kopp fled the country, hiding in Mexico, Ireland, and France. He is currently a suspect in four other non-fatal shootings of abortion providers and has been charged with the 1995 attempted murder of a doctor in Ontario, Canada.