One of the few remaining late-term abortion providers in the country told ABCNews.com that he fears he could be "next" following this weekend's murder of controversial abortion doctor George Tiller.
"Every doctor who performs abortions is on the list," said Dr. Warren Hern about the names of doctors willing to perform the procedure he says anti-abortionist groups track and publicize.
Hern's Boulder Abortion Clinic has been specializing in late-term abortions since it was founded in 1975.
"I'm appalled and shocked by this assassination, but I'm not surprised," Hern said of Tiller's death. "This is not the single act of a deranged gunman. This is the absolutely predictable result of 35 years of anti-abortion harassment."
"Tiller's death is what they want to happen," said Hern, who declined to specify on the degree to which security at his clinic has been ramped up since Tiller's murder on Sunday.
Sarah Huntley, a spokeswoman for the Boulder Police Department, said that there have been an increased number of patrol cars sent to monitor the areas near Hern's house and clinic since Tiller's death.
But perhaps more telling, said Huntley, is that most of the security responsibilities concerning Hern and his staff have been handed over to the U.S. Marshall Service, a move she deems "unusual."
A spokesman for the U.S. Marshall Service told ABCNews.com that it is against their policy to comment on protective details.
Scott Roeder, the man accused of shooting Tiller in church, is expected to be charged today with homicide.
Roeder, 51, has a history of being one of the most outspoken anti-abortion militants in the country, according to the Southern Poverty Law Center, an organization that tracks supremacist and hate groups. One of the groups that the SPLC kept an eye on was the anti-government Freemen movement, of which Roeder was a member.
"[Roeder] wanted to do something about abortion," said Morris Wilson, who was close with Roeder during the late 1990s when both men were associated with the Freemen movement.
"He was determined," said Wilson. "He made me nervous because he was just so, so radical."
In 1996, Roeder was charged in Topeka with criminal use of explosives for having bomb components in his car trunk and sentenced to 24 months of probation. However, his conviction was overturned on appeal the next year after a higher court said evidence against Roeder was seized by law enforcement officers during an illegal search of his car.
At the time, police said the FBI had identified Roeder as a member of the Freemen, which had kept the FBI at bay in Jordan, Mont., for almost three months in 1995-'96.
Heidi Beirich, a spokeswoman for the SPLC, said that the Freeman movement has been dormant in recent years and that the group has not been categorized as a functioning group since the late 1990s.
"The Freemen has its heyday in the 1990s," she said. "They were an extreme anti-government group that did not believe for example that the government had the right to decide what people should do in terms of guns or taxes."
At least one of Roeder's former militants doesn't believe he did anything wrong.
Ex-Freeman Accused of Shooting Tiller
Regina Dinwiddie, a Kansas City anti-abortion activitist who became famous when she was ordered by a federal judge in 1995 to stop using a bullhorn within 500 feet of any abortion clinic, said that she had protested alongside Roeder and remembers him fondly.
"I think the Scott Roeder that I know is a very pleasant and intelligent young man," said Dinwiddie, reached at her home in Kansas City, Mo.
Asked whether she thought Roeder was capable of murder, Dinwiddie said that she doesn't think Tiller's death was murder.
"I don't think whoever shot Tiller shot anybody," Dinwiddie said. "I think Tiller was stopped from killing the babies that would have died today. I think whoever shot him just stopped a cold blooded serial murderer in their tracks."
Dinwiddie said that she knew Roeder did not "like people killing babies," but was "very pleasant" and had a "good heart."
Roader's ex-wife, Lindsey Roeder, told police searching her home Sunday that her husband was likely involved in Tiller's death.
Lindsey Roeder said it was Scott Roeder's strong anti-abortion views that led to the couple's 1996 divorce. She said her ex-husband never kept quiet about his views on abortion.
"My family does not condone or support what Scott has done. This event is a tragic and senseless one and our thoughts and prayers are with the congregation and the doctor's family," Lindsey Roeder said.
Lindsey Roeder said Scott Roeder was adamant about seeing his 22-year-old son, Nick, Friday night. She claimed their son has tried to avoid his father and only saw him about once every six weeks growing up.
"My son is only related to his father by blood and does not believe in any of the same views his father does," Lindsey Roeder said.
The two did meet Friday night, she said, and she believes the meeting was meant as a goodbye from father to son.
Tiller's lawyer and friend, Lee Thompson, told "Good Morning America" today that Tiller, 67, was "one of the most positive and courageous men I've ever known."
Tiller Wore Bulletproof Vest and Used Armored Car
Thompson said Tiller had a sort of "servant" attitude toward his patients, believing that helping women in distress was his duty even though he often wore a bulletproof vest to work and drove an armored car.
"Dr. Tiller always said he fell in love with the doctor-patient relationship," he said.
Tiller, who ran the Women's Health Care Services clinic, a high-profile abortion clinic in Wichita, was one of the few doctors in the country that still performed late-term abortions. Earlier this month, Tiller's clinic was vandalized, according to reports.
Tiller has long been a target of anti-abortion activists. His clinic has often been the scene of nonviolent protests, but he was also shot outside his clinic in 1993 and his clinic was bombed in 1985.
In a 1991 interview, Tiller said he had a right to go to work each day.
"What I'm doing is legal. What I am doing is moral. What I'm doing is ethical," he said. "And you're not going to run me out of town."
Tiller is believed to be the first abortion doctor to be killed since Barnett Slepian was assasinated in Amherst, N.Y., in 1998.