DENVER » Victims of a mass shooting at a Colorado Planned Parenthood clinic say more should have been done to prevent the attack, given the long history of violence against the reproductive health organization.

The Colorado Springs clinic should have known it was a target for violence, but it lacked armed guards, adequate fencing and other security measures during the Nov. 27 attack, according to a lawsuit filed Friday. Three people were killed and nine others injured in the shooting and five-hour standoff.

Whitney Phillips, a spokeswoman for Planned Parenthood of the Rocky Mountains, declined to comment on the lawsuit. But she said the organization prioritizes safety and believes its facilities are safe and inviting for patients and staff.

Robert Dear, 57, has acknowledged opening fire at the clinic, telling investigators he was upset with Planned Parenthood for “the selling baby parts.” A judge this month declared him incompetent and ordered him to undergo psychiatric treatment before his criminal case can proceed. In courtroom outbursts, Dear declared himself a “warrior for the babies” and said he was guilty. He has not entered a plea to 179 counts of murder, attempted murder and other crimes.

Other Planned Parenthood clinics, including a larger facility in Denver, had armed guards, tall gates and audio and video surveillance, said attorney Kirk McCormick, who filed the lawsuit on behalf of Samantha Wagner, who was shot; Ashley Stewart, whose husband, Ke’Arre Stewart, was killed; and the couple’s child.

McCormick cited a decades-long history of violence against the organization, including thousands of threats and hundreds of attacks such as arsons, bombings and killings of doctors and staff. The FBI sent abortion providers an alert just two months before the shooting, warning of the increased likelihood of violence. Yet, the lawsuit says, the clinic failed to properly train employees or post signs warning of potential danger.

“They were on notice. They should have had appropriate security in place, and they just didn’t have any,” McCormick said.

The lawsuit comes days after a jury found movie theater chain Cinemark not to blame for a 2012 shooting at a Colorado theater that left 12 people dead and more than 70 others injured. But unlike that case, the clinic shooting was predictable because similar attacks have happened before, McCormick said.