Scott Roeder

Scott Roeder, 51, was charged with first-degree murder in connection with the May 31 assassination of Tiller, who was shot while serving as an usher at his church. Tiller, who in 1993 was shot in both arms by another anti-abortion protester, ran one of three clinics in the United States that provided late-term abortions.

Roeder was involved during the '90s with the so-called sovereign citizens movement. Sovereign citizens generally believe the government has no jurisdiction over them and often deluge courts with phony liens and other paperwork. Many of them also believe that only whites can be sovereigns, while blacks and others are mere "14th Amendment citizens" who must obey all government rules.

Police stopped Roeder in 1996 because he didn't have a valid license plate and instead was using a tag that declared he was a "sovereign" citizen who didn't have to obey the government. During a search of his car, police discovered bomb-making materials including gunpowder and a homemade fuse. He was found guilty of criminal use of explosives, but an appeals court ruled that the car had been improperly searched and overturned the conviction.

Dave Leach told reporters that Roeder had contributed to his newsletter, Prayer and Action News, which argues that killing abortion providers is justifiable. A former roommate told CNN that Roeder belonged to the "Army of God," whose website praises the killings and asserts that Tiller is now in hell. Roeder also made inflammatory posts to Operation Rescue, a Wichita-based group that long had tried to prevent Tiller from providing late-term abortions. In one 2007 post, Roeder wrote: "Tiller is the concentration camp 'Mengele' of our day and needs to be stopped before he and those who protect him bring judgment upon our nation."

Roeder's family said he has suffered from bouts of mental illness.

Roeder may also have vandalized a Kansas City clinic shortly before he allegedly shot Tiller. A man repeating phrases such as "baby killer" was spotted using super glue to jam a door lock at the Aid for Women clinic the day before Tiller's death. He fled in a car with the same license plate as Roeder's vehicle.

Speaking with The Associated Press after his June arrest, Roeder said: "I know there are many other similar events planned around the country as long as abortion remains legal." He would not say if he was referring to killings.

Since 1977, eight U.S. abortion providers or their assistants or escorts have been killed, including Tiller, according to the National Abortion Federation. After the latest murder, Tiller's family said his clinic would not be reopened.