It's called the "lone wolf" model -- one person inspired by others but acting alone to commit violence.
That's the strategy some militant anti-abortion activists say Scott Roeder followed. Roeder is charged with murder in the shooting death of Wichita abortion provider George Tiller on May 31.
Federal authorities are now investigating whether Roeder was part of a conspiracy of activists whose goal is to kill doctors and shut down abortion clinics.
Interviews last week and court documents suggest that Roeder had a number of connections with militant abortion foes but few formal ties with known groups. One religious group he once studied under rejects all government authority, and he protested at abortion clinics with others who advocated killing doctors.
One of those abortion foes contends Roeder acted alone in allegedly shooting Tiller.
"People with common sense who hate the killing of children are going to act without consulting others, because they don't want to get other people in trouble," said Regina Dinwiddie, a Kansas City abortion opponent who sees Roeder as a hero.
Abortion-rights advocates say that even if that's true, it's still a conspiracy -- those who support killing doctors and praise the violent acts should be held just as accountable as those who pull the trigger, they say.
"Their language is so over the top that there's no way that the permission, the encouragement, to do these kinds of activities is not implicit in that," said Ann Glazier, former director of security for Planned Parenthood Federation of America.
"This is literally standing up in a crowded theater yelling 'fire,' but yelling 'fire' when there are a bunch of arsonists in the room."
Five days after Tiller's death, the U.S. Department of Justice announced it had launched a federal investigation into the murder.
"The Department of Justice will work tirelessly to determine the full involvement of any and all actors in this horrible crime, and to ensure that anyone who played a role in the offense is prosecuted to the full extent of federal law," said Loretta King, acting assistant attorney general for the Civil Rights Division.
Mainstream anti-abortion groups have decried Tiller's murder.
Some militant groups and abortion opponents applaud the slaying but deny they played any role in it.
Instead, they describe Roeder as a "lone wolf," a term terrorism experts also use to describe someone who is inspired by an ideology or an organization to commit violence, but acts independently. Such people may be encouraged by or receive support from others, but they plan and commit the act on their own.
One example is Eric Rudolph, convicted of a 1998 abortion-clinic bombing in Birmingham, Ala., and the bombing at the 1996 Atlanta Summer Olympics. Two people died and one was maimed in those attacks.
The lone-wolf model is a solitary version of a strategy called "leaderless resistance," which encourages small, independent cells to commit violent acts. Timothy McVeigh, who committed the Oklahoma City bombing, was part of such a cell.
Questions also are being raised as to whether the man charged in last week's attack on the Holocaust Museum in Washington, D.C., is a lone wolf as well. James von Brunn, a white supremacist, is accused of storming into the museum with a rifle and killing a black security guard Wednesday afternoon.
Federal officials have said in reports that lone-wolf attacks are more difficult to prevent and have become more of a concern in recent years.
Alone or affiliated?
At the heart of the federal investigation is the issue of whether Roeder acted alone.
Roeder claimed from his jail cell last week that similar violence is planned around the nation for as long as abortion remains legal.
Whether he had knowledge of such plans is for investigators to determine, but the picture of his ties and influences has become more clear in recent days.
Documents from his 1996 divorce case indicate he was affiliated with the Embassy of Heaven Church in Stayton, Ore., during much of the 1990s. The group's leader, who goes by the name Paul Revere, wrote letters to Johnson County court officials in 1999 offering to pay Roeder's back child support.
"We have faithfully informed the District Court Trustee that Scott P. Roeder is on assignment for us in the mission field and that we are handling his affairs," Revere wrote Aug. 10, 1999.
Revere said that Roeder wanted his wife and child to "return to his side," saying that would be biblical.
Revere told the Kansas City Star on Thursday that the Embassy of Heaven was "a country."
"We represent the Kingdom of Heaven, God's government on Earth," he said. The group issues its own driver's licenses, identity cards and passports for members. Over the years, followers have found themselves in legal trouble for rejecting government authority.
Revere said he didn't know Roeder had been charged in Tiller's death. After checking Roeder's file, Revere said Roeder during the 1990s had been training with and receiving materials from the Embassy of Heaven but never "made his statement of citizenship in the Kingdom of Heaven."
Revere said he never met Roeder and that after he sent the letters to the court on Roeder's behalf, he never heard from him again.
Revere said his group did not condone Tiller's killing. "Killing anybody is a violation of our law," he said.
The Embassy of Heaven is listed in a 1997 directory as a Christian Identity organization, but Revere said his group had nothing to do with the Identity doctrine.
"We get placed on every list out there," he said.
Christian Identity is a race-based religious movement that teaches that Jews are satanic and that nonwhites are inferior. In the past 25 years, adherents have been convicted of robberies, bombings and murders, engaged in shootouts with police and plotted assassinations and the overthrow of the government to attain their stated goal: a white Christian nation.
Roeder's ex-wife, Lindsey Roeder, said in an interview last week that she told the FBI about the Embassy of Heaven.
"I used to hide their literature from Scott," she said. "He wanted to send the title of our car to them."
She said Roeder didn't talk about Christian Identity but said he didn't like blacks and "talked about the Federal Reserve and that it's run by the Jews."
She said she also saw the book "The Turner Diaries" among the literature Roeder kept in the house. The novel, which is about a violent overthrow of the government by a band of white supremacists, was thought to have inspired McVeigh in the Oklahoma City bombing.
Leonard Zeskind, a Kansas City expert on right-wing extremism and author of the recently published book "Blood and Politics," said Roeder had all the characteristics of a Christian Identity follower.
"He was anti-tax, he declared himself to be a sovereign... immune to the laws of government," Zeskind said. "While he may seem to be a militia guy one day, a tax protester the next and anti-abortion the next, it's not a fragmented personality. It's one theologically driven personality, and that theology stakes out the establishment of God's kingdom on earth and the laws as they see that God established them."
Roeder's other ties included the Freemen movement, which claimed sovereignty from government jurisdiction and operated under its own legal system, prosecutors say. Associates say he also was involved in a Topeka-based militia group, the Kansas Unorganized Citizens Militia.
Morris Wilson, a commander of that militia, said Roeder came to meetings in the mid-1990s.
"Actually, Roeder was more interested in the Freemen and their beliefs," Morris said. "He was more loosely associated with the militia."
Attempts to reach Roeder were unsuccessful.
Lindsey Roeder said her ex-husband first got involved in the abortion issue and anti-government movement in the early 1990s.
One day in 1992, when their son was 5, she said, Roeder showed him graphic pictures of aborted fetuses. Four years later, she said, she and their son visited Roeder in Topeka when he was on probation following his conviction for possessing bomb-making materials. It was then that he revealed to them why he was driving around with explosives in his car.
"He said he was going to blow up an abortion clinic," she said. "But he didn't intend to hurt anyone. He was going to do it at night when nobody was there."
Roeder also knew Shelley Shannon, the woman prosecutors believe acted as a lone wolf when she shot and wounded Tiller in 1993, according to an anti-abortion activist who has stayed in contact with Shannon while she's been in prison.
Dave Leach, publisher of Prayer & Action News -- a magazine that advocates justifiable homicide for abortion doctors -- told the Star that Roeder visited Shannon in prison in Topeka when she was serving time for shooting Tiller. Shannon is now in federal prison, serving a 20-year sentence for committing a series of clinic bombings and arsons in the Pacific Northwest.
The Rev. Donald Spitz, leader of Pro-Life Virginia and sponsor of the Army of God Web site, said Shannon has been writing to people from prison, encouraging them to support Roeder and send him money. He shared part of a letter she sent to a supporter after Tiller's death.
Shannon wrote that when she heard of Tiller's murder, "I almost thought I saw a whole cloud of babies clapping, like a standing ovation."
Others have been supporting Roeder as well. Anthony Leake, an anti-abortion activist who for years has vocally supported the killing of abortion doctors, said he had been trying to get Roeder a lawyer other than the public defender who has been assigned to him.
"I've got attorneys lined up that are willing to go talk with him," Leake said. "But they haven't been able to get in."
Spitz's Army of God Web site is a tribute to those who have committed violence against abortion clinics and doctors. Last week, it featured a picture of Tiller being taken out of his church in a body bag with flames superimposed underneath and the words that Tiller "is now in eternal hell."
Spitz denies the charges of abortion-rights advocates who say the site encourages activists to kill doctors.
"They just want to silence us," he said.
But such militant groups do inspire violence, said Brian Levin, director of the Center for the Study of Hate and Extremism at California State University at San Bernardino.
"That's what (the lone-wolf model) is designed to do," Levin said. "It's designed to limit the reach of law enforcement by sending out unstable martyrs to do the dirty work of an otherwise mysterious movement."
That's what makes it dangerous, he said.
"This is something that's encouraged as a tactical method, but it's also encouraged as a moral, folkloric method," Levin said.
Even if attackers act alone, abortion-rights supporters want federal authorities to take swift action.
"This is madness," said Warren Hern, director of the Boulder Abortion Clinic, which since Tiller's death is one of the few clinics in the country performing late-term abortions. "These are fanatics. It's a terrorist movement, it's a fascist movement. They talk to God and carry guns. The only difference between the American anti-abortion movement and the Taliban is about 8,000 miles."
But Leake, who was subpoenaed by a federal grand jury in Virginia in 1995 that was investigating violence against clinics and doctors, said he doesn't expect authorities to find any conspiracy.
"Conspiracies are very difficult to prove," he said.