In March, Tiller was acquitted of 19 misdemeanor charges that he performed abortions illegally, failing to follow state law and obtain a second opinion on late-term abortions.
Under Kansas state law, abortion is legal only when a doctor affirms that the fetus can't live independently outside of the mother's womb, also known as determining viability. If the fetus is viable, two doctors must attest that the abortion is necessary for the well-being of the mother's physical or mental health.
A longtime acquaintance of the doctor from the Wichita Country Club who did not want to use her name told ABC News.com that the news of his death was extremely upsetting.
"It infuriates me," she told ABCNews.com. "He was shot in church. He was persecuted by some radical thinking individuals.
"He was well-respected in many circles in Wichita and had a presence about him," she added. "You could look at him and tell he was a man of character."
The homicide has shaken up the upper-middle-class neighborhood of East Wichita, where violence is relatively uncommon.
"Any community is diminished by a homicide ... and Wichita certainly no different than any other community in the country," Bassham said.
A candlelight vigil is scheduled to take place Sunday evening in Wichita's Old Town Square to show support for Tiller's family.
President Obama issued a statement saying he was "shocked and outraged" by the killing, and saying such actions cannot help settle the debate over abortion.
"I am shocked and outraged by the murder of Dr. George Tiller as he attended church services this morning," he said. "However profound our differences as Americans over difficult issues such as abortion, they cannot be resolved by heinous acts of violence.
Kim Gandy, president of the National Organization for Women, which supports abortion rights, decried the killing of Tiller as a form of terrorism.
"If they think that by killing Dr. Tiller they are going to stop women's access to abortions, they're wrong … because there will be another doctor, and another, and another," she told ABC News Radio. "These people are organized. ...They're raising money and funding domestic terrorism."
Operation Rescue, an anti-abortion rights group that has denounced the practices of Tiller for years and staged mercy demonstrations outside the clinic in the summer of 1991, also condemned the murder.
"We are shocked at this morning's disturbing news that Mr. Tiller was gunned down," the organization said in a statement. "Operation Rescue has worked for years through peaceful, legal means, and through the proper channels to see him brought to justice. We denounce vigilantism and the cowardly act that took place this morning. We pray for Mr. Tiller's family that they will find comfort and healing that can only be found in Jesus Christ."
However, a statement by Operation Rescue's founder, Randall Terry, sounded a more fiery note.
"George Tiller was a mass-murderer," Terry's statement said. "We grieve for him that he did not have time to properly prepare his soul to face God. I am more concerned that the Obama administration will use Tiller's killing to intimidate pro-lifers into surrendering our most effective rhetoric and actions. Abortion is still murder. And we still must call abortion by its proper name; murder."