These are dangerous people-join the FBI if you want to do this type of work. You'd be dealing with people who engage in, support, or defend the use of force (vandalism, arson, bombings, kidnapping, stalking, assault, attempted murder, and murder) — as justifiable homicide or defense of others — in interest of protecting the life of the fetus: http://www.rickross.com/reference/a-abortion/a-abortion5.html
In the U.S., violence directed toward abortion providers has killed 7 people, including 3 doctors, 2 clinic employees, a security guard, and a clinic escort: http://www.prochoiceamerica.org/assets/files/Abortion-Access-to-Abortion-Violence.pdf
Who have these particular "pro-life" people murdered?:
March 10, 1993: Dr. David Gunn of Pensacola, Florida was fatally shot during a protest. He had been the subject of wanted-style posters distributed by Operation Rescue in the summer of the year before. Michael F. Griffin was found guilty of Dr. Gunn's murder and was sentenced to life in prison.
June 29, 1994: Dr. John Britton and James Barrett, a clinic escort, were both shot outside of another facility in Pensacola. Rev. Paul Jennings Hill was charged with the killings, received a death sentence, and was executed September 3, 2003.
December 30, 1994: Two receptionists, Shannon Lowney and Lee Ann Nichols, were killed when two separate clinics in Brookline, Massachusetts and Norfolk, Virginia were both attacked on the same day. John Salvi was later convicted. He committed suicide in prison and guards found his body under his bed with a plastic garbage bag tied around his head.
January 29, 1998: Robert Sanderson, an off-duty police officer who worked as a security guard at an abortion clinic in Birmingham, Alabama died when his workplace was bombed. Eric Robert Rudolph, who was also responsible for the 1996 Centennial Olympic Park bombing, was charged with the crime and received two life sentences as a result.
October 23, 1998: Dr. Barnett Slepian was shot dead at his home in Amherst, New York. His was the last in a series of similar shootings against providers in Canada and northern New York state which were all likely committed by James Kopp. Kopp was convicted of Dr. Slepian's murder after finally being apprehended in France in 2001.
A fourth doctor, George Patterson, was shot in Mobile, Alabama on August 21, 1993, but it is uncertain whether his death was the direct result of his profession or rather a robbery: http://www.plannedparenthood.org/news-articles-press/politics-policy-issues/abortion-access/tiller-patterson-11504.htm
According to NAF, since 1977 in the United States and Canada, property crimes committed against abortion providers have included 41 bombings, 173 arsons, 91 attempted bombings or arsons, 619 bomb threats, 1630 incidences of trespassing, 1264 incidences of vandalism, and 100 attacks with butyric acid ("stink bombs"): http://www.prochoice.org/pubs_research/publications/downloads/about_abortion/violence_statistics.pdf
Some of the latest incidents:
April 25, 2007: A package left at a women's health clinic in Austin, Texas contained an explosive device capable of inflicting serious injury or death. A bomb squad detonated the device.
May 9, 2007 An unidentified person deliberately set fire to a Planned Parenthood clinic in Virginia Beach, Virginia: http://www.wtkr.com/Global/story.asp?S=6492086
The most dangerous groups who oppose abortion either explicitly or implicitly advocate violence against abortion providers:
1) The Army of God, an underground network of activists who believe that the use of violence is an appropriate tool for fighting against abortion: http://www.armyofgod.com/
2) American Coalition of Life Activists, who published the Nuremberg Files: http://archive.salon.com/news/feature/2001/05/31/nuremberg/
These are extremely dangerous domestic terrorists. Please don't try to deal with them unless you are a professional with the legal backing and protection of the FBI.