The Colorado Springs Planned Parenthood shooting was a shock but, sadly, not a surprise. In the past four months, at least four separate groups have warned that the undercover video campaign from the Center for Medical Progress (CMP), which alleged that Planned Parenthood illegally profited from its fetal tissue donation program, could result in an escalation of violence against abortion providers.

In a July 31 application (PDF) for an injunction against CMP founder David Daleiden and his organization, the National Abortion Federation (NAF) noted that there were already telling warning signs of anti-abortion violence, just 17 days after the release of the first undercover video. In addition to relaying death threats received by Planned Parenthood doctors, the NAF noted that their security staff had received “an increase in ‘off’ hour requests for security advice from its members” and that they had advised abortion providers to “be on heightened alert.”

Most immediately concerning, however, was the NAF’s claim that “incidents of harassment at Planned Parenthood facilities increased nine fold in July, compared to reported incidents in June, and the reported incidents of harassment were even more numerous in August.”

NAF President and CEO Vicki Saporta noted a “dramatic increase” in harassment since July 14, and recounted phone calls to clinics in which people made “threats [that] they are going to kill every doctor at the facility.”

“Let’s pull a Columbine,” one caller allegedly said.In an interview with The Huffington Post, Saporta said, “In my 20 years at NAF, I have never seen such a volume, intensity, and escalation of hate speech, threats, and criminal activity, and we would like to prevent a serious violent act from occurring.”

Law enforcement was also concerned about an increased risk of violence following the release of the CMP videos. In September, CBS reported that an FBI Intelligence Assessment warned that “it is likely criminal or suspicious incidents will continue to be directed against reproductive health care providers, their staff, and facilities.”

The document further noted that a recent uptick in criminal or suspicious incidents following the CMP videos was “consistent with the actions of lone offenders using tactics of arsons and threats all of which are typical of the pro-life extremist movement.” One of the nine incidents they listed was in Denver.Planned Parenthood itself has also warned about the effects the videos could have on a culture of anti-abortion extremism, despite the fact that the organization has been repeatedly cleared of allegations of criminal wrongdoing.On Nov. 10, a little over two weeks prior to the shooting, Planned Parenthood President Cecile Richards told Katie Couric that vandalism had increased at affiliates around the country, making it challenging to recruit clinicians.“Given this current environment and the hostility that some of the extremists have and their willingness to kind of go to these depths to shame doctors, it’s very tough,” Richards said.

Then there are the high-profile incidents themselves. There have been four arsons or attempted arsons at Planned Parenthood since July—a pattern that prompted anti-abortion terrorism expert David S. Cohen to tell the Southern Poverty Law Center’s Hatewatch, “It’s scary to contemplate what might happen next.”

Cohen was one of a group of 32 attorneys who signed a letter to California Attorney General Kamala Harris in July warning that the video campaign posed “a real threat to abortion provider safety.”

“Given the unique risks that abortion providers face of being targeted by anti-abortion extremists, abortion providers whose images and names are blasted across the Internet in this fashion face grave threats to their and their family’s safety,” the letter read.

After months of warning from multiple organizations, there has finally been a high-profile attack on an abortion provider that resulted in loss of life.

On Nov. 27, Robert Lewis Dear entered the Planned Parenthood clinic in Colorado Springs with “duffel bags full of rifles and handguns” and allegedly killed a police officer and two civilians. In the history of violence against abortion providers, this could be the first murder since the 2009 assassination of Dr. George Tiller and the closest event to “a Columbine” since 1994 when John Salvi fatally shot two receptionists in two different Massachusetts abortion clinics within minutes of each other.

Until Dear goes to trial, it will be impossible to pinpoint the precise catalyst for the shooting and difficult to say if or how closely he was influenced by the CMP videos. Since the shooting, Cecile Richards has stopped short of attributing Dear’s alleged actions to current anti-abortion rhetoric while still warning of an “incredible escalation of harassment and intimidation” at abortion clinics.We can reasonably assume, however, that Dear had at least caught wind of the conversation around the CMP’s allegations against Planned Parenthood. Two law enforcement sources told NBC News that Dear said, “No more baby parts,” after being taken in for questioning. “Planned Parenthood Uses Partial-Birth Abortions to Sell Baby Parts” was the title of the first CMP video and #PPSellsBabyParts was the hashtag through which that video spread on social media.

And on Tuesday, an anonymous source who had extensive conversations about religion with Dear told the The New York Times that the accused gunman described those who attacked abortion providers as doing “God’s work” and called the Christian terrorist organization Army of God, which has claimed responsibility for several bombings and abortion clinic attacks, “heroes.”Based on the Army of God website, the admiration appears to be somewhat mutual. Their description of the Colorado Springs shooting currently reads, “These murderous pigs at Planned Parenthood are babykillers [sic] and they reap what they sow. In this case, Planned Parenthood selling of aborted baby parts came back to bite them.”

No matter Dear’s precise motive, his alleged act of violence at an abortion provider could prove to be the most extreme in decades. Based on NAF statistics, (PDF), Dear stands accused of killing as many people in seven hours in an abortion provider as have died from anti-abortion violence in the previous 20 years combined.

And whatever led Dear to walk through the doors of the Colorado Springs clinic last Friday, the political climate following the Colorado Springs shooting is already eerily reminiscent of previous killings in anti-abortion history, with some of the most extreme voices on the right walking a fine and dangerous line in their response to the shooting.On Tuesday, RedState founder and conservative pundit Erick Erickson wrote, “It really is surprising more Planned Parenthood facilities and abortionists are not being targeted.”

“Given the public light shed on the atrocities committed by Planned Parenthood and both the government and media’s turning a blind eye to it, dismissing it, laughing it off, or lying about it, it really should be surprising that Americans convicted of the need to stop the murder of children have not taken the law into their own hands,” he continued.

But one development in the Colorado Springs shooting is troublingly different from past cycles of violence and rhetoric.

As The New Yorker noted Tuesday, Dear does not fit the standard profile of previous anti-abortion killers, most of whom professed ties to groups like Operation Rescue, which is now funding the CMP, and Army of God. Pro-life leaders in Colorado Springs have said that they are not familiar with Dear and his online writings have yet to turn up any clear links to anti-abortion groups.

And unlike past shootings, many of which clearly targeted specific doctors, Dear’s alleged actions—with the present limited information, at least—seem to have more in common with recent mass shootings at schools, churches, and other public venues than they do with anti-abortion assassinations.Dear’s case, then, could be a continuation of past violence at abortion providers but he could also prove to be something even more alarming: a new face of anti-abortion extremism in the age of the mass shooting.Either way, one of the most frightening things about Dear is just how many people seem to have seen him coming from so far away.