The man accused of killing three people at an abortion clinic in the US said “no more baby parts” when he was arrested, according to media reports.
Police have not said why the Planned Parenthood centre in Colorado Springs was attacked.
However, the city’s mayor John Suthers said people could make “inferences from where it took place”.
The facility has repeatedly been targeted by anti-abortion protesters, who have demanded its closure.
A police officer and two civilians were shot dead in the rampage and nine others were wounded. The survivors are all recovering in hospital.
The two civilians have yet to be identified but the policeman has been named as father of two Garrett Swasey, 44.
The alleged gunman, 57-year-old Robert Lewis Dear, gave himself up after a five-hour standoff with police.
Dear, from South Carolina, is due to make his first court appearance on Monday.
Neighbours have described him as a loner and strange but not dangerous. They say he hid food in the woods and liked to swim naked.
On Saturday afternoon a vigil was held for the shooting victims at the Unitarian Universalist Church.
At the service the president of Planned Parenthood’s Colorado branch said the organisation would not be cowed by the attack.
“What happened yesterday was a terrible crime and we will never forget it,” said Vicki Cowart.
“But we will adapt, we will square our shoulders, we will go on, we will show up for work on Monday, and we will begin again.”
The attack was also condemned by President Barack Obama who said it once again illustrated the need to tighten America’s gun laws.
“We have to do something about the easy accessibility of weapons of war on our streets to people who have no business wielding them,” he said.
He added: “Period. Enough is enough.”
Planned Parenthood is a non-profit organisation which runs hundreds of clinics across the US providing services such as contraception and STD testing, as well as terminations.
Ms Cowart said she did not know If it was the object of the attack.
But she added: “We share the concerns of many Americans that extremists are creating a poisonous environment that feeds domestic terrorism in this country.”
In July anti-abortion campaigners released an undercover video which they claimed showed Planned Parenthood staff negotiating the sale of foetal organs.