For US Democrats, the attack carried out at a family planning center was a repercussion of virulent conservative anti-abortion rhetoric. The accusation appalls Republicans, who focus on the shooter`s mental disorders.
Robert Lewis Dear, a 57-year-old recluse, is accused of killing a police officer and two others last Friday at a Planned Parenthood facility in Colorado Springs, one in a network of 700 clinics nationwide.
According to NBC News which quoted law enforcement officials, Dear mentioned "no more baby parts" upon his arrest.
Investigators have not confirmed the killer`s motives, but the words "baby parts" were repeated for months by Republicans in Congress and in the White House race as they blasted Planned Parenthood, which stood accused of profiting from the sale of fetal tissue.
The Democratic governor of Colorado, John Hickenlooper, was among those who suggested at the weekend that the gunman may have been driven to act by "inflammatory rhetoric" on the US airwaves, coming both from anti-abortion politicians and talk show hosts.
"I think maybe it`s time to look at how do we tone down some of that rhetoric," Hickenlooper told CNN, "so we don`t get people to a point of going out and committing senseless violence."
The Planned Parenthood controversy erupted in July when anti-abortion activists publicized secretly-filmed footage showing the organization`s staffers discussing the procedures for donating fetal tissue to the scientific community for medical research.
Only a handful of clinics allow such donations, which are authorized by law. Payment for the service is prohibited, although compensation for costs such as transportation is allowed.
Amid intense controversy in the conservative world, Planned Parenthood announced in October it would no longer accept compensation for the service in order to avoid the appearance of financial gain.
Still, Republicans continue to accuse Planned Parenthood of acting illegally, and many in the party want to end all federal funding for the group, which also performs cancer screenings and other health services for millions of women.
Democratic frontrunner Hillary Clinton implicitly linked Friday`s killings with the hostility fueled by conservatives against the organization, which they view as a symbol of the abortion rights upheld by the Supreme Court in 1973.
"We should be supporting Planned Parenthood, not attacking it," she said Sunday in New Hampshire, before blaming Republicans for blocking any tightening of America`s gun laws.
"I strongly support Planned Parenthood and its work and hope people realize that bitter rhetoric can have unintended consequences," added Senator Bernie Sanders, Clinton`s top challenger for the Democratic nomination, on Saturday.Planned Parenthood`s president Cecile Richards also set out to remind those in the intense debate that "words matter."
"Whether you`re a politician or whether you are in elected office, or whether you`re an opposition group, this kind of rhetoric towards doctors and women seeking health has real impact," she told National Public Radio on Monday.
While many Republicans claimed solidarity with France within minutes of the deadly attacks in Paris, it took days for Republican presidential contenders to publicly address the Colorado Springs shooting.
Many called for caution before weighing in on the killer`s motives.
"This man is mentally ill," House Majority Leader Kevin McCarthy told reporters Monday. But he declined to say whether Republican rhetoric over Planned Parenthood had gone too far towards feeding a toxic atmosphere.
"He was crying out" for treatment for mental illness and "shouldn`t have been able to have weapons," House Republican Darrell Issa told Fox News.
Conservatives have denounced rival Democrats for what they say is political exploitation of the shooting, and defended their battle against abortion.
Those opposed to abortion in the United States call their movement "pro-life," while supporters of abortion rights have embraced the "pro-choice" label.
Anyone who linked the Colorado Springs killings to the pro-life movement was using "typical left-wing tactics," said Carly Fiorina, who as the only woman in the Republican nomination race has accused Planned Parenthood of "butchering babies for body parts."
Family planning clinics have been under threat for decades. Staff are trained to react to intrusions, and the clinics are often protected by security guards or police.
Despite Friday`s attacks, Planned Parenthood`s facilities remained open at the weekend.
Since 1977, eight people connected to abortion clinics have been killed, and there have been 17 attempted murders, 42 bombings and 186 arson attacks, according to the National Abortion Federation.
The previous murder took place in 2009, when doctor George Tiller of Kansas was killed.
Figures for 2015 had yet to be compiled, but the trend, according to the federation, is clear since the July release of the videos, which Planned Parenthood were doctored to misrepresent its stance.
"We have seen an unprecedented increase in hate speech and threats against abortion providers," federation president Vicki Saporta said.