COLORADO SPRINGS, Colo. -- Authorities say a man who killed three people during a rampage in Colorado Springs was armed with three guns he purchased legally six years earlier.

The El Paso County sheriff's office said Thursday that 33-year-old Noah Harpham had an AR-15 rifle, a 9 mm pistol and a .357 revolver when officers fatally shot him Saturday.

Witnesses said he used the rifle to kill a bicyclist and two women who were on the porch of a sober living home before dying in a gunbattle with police.

The sheriff's office says Harpham bought the guns in 2009, as he had no criminal record preventing him from purchasing them. A motive for the killings remains unknown.

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Harpham gave no indication that he was planning violence in a one-minute online video posted two days before the shooting.

Harpham posted a blog not long before the shootings took place Saturday morning, reports CBS Denver. The statements on the blog appear to be ramblings about his father's connection to a church in California. They make no mention that he might be about to go on a killing spree.

Witnesses have painted a terrifying scene during the shooting rampage.

A neighbor, Teresa Willingham, said she and her 7-year-old son heard three loud gunshots and saw a bicyclist lying face down in the street, his legs mangled and still intertwined in his bike.

Police investigate after shooting left four people dead, including the gunman, in Colorado Springs, Colo., on October 31, 2015. KKTV

"His last words were 'Please God, no,'" she said. "He was just at the wrong place at the wrong time."

A neighbor, Naomi Bettis, who lives across the street, said she saw a man in a green jacket with a rifle, walking down the street. She saw him go into a house, and come out with a gun. She said the man headed down the block, and a bicyclist came up.

Bettis said the bicyclist begged for his life, but the gunman started shooting.

Bettis said the bicyclist collapsed outside a house. She later placed a bouquet of flowers, a candle and a note where the bicyclist was slain, saying "My thoughts are with you. Praying for the family. I'm sorry for your loss."

After the first shooting, the gunman took off running, and according to witnesses who talked to CBS affiliate KKTV, he just began shooting at anyone in his way, hitting a few.

One of those witnesses, Matt Abshire, said: "I looked out my kitchen window and I saw a man in a green jacket firing an AR-15...waited a few seconds, went out of my house, looked to my left and saw a man down the street, probably 50 feet. I started following him and I called the cops."

Abshire said one of the victims was dead by the time he got to her, and that police encountered the gunman moments later outside a Wendy's.

Aaron Nicks and dozens of other people in downtown Colorado Springs watched in horror as police exchanged gunfire with the suspect.

"I was just sitting on my patio taking my dog out when I saw someone come around the corner, being chased by the police," he told KKTV.

Police say they spotted the gunman several blocks away, where a shootout erupted. Photos show a window in the back of a police car that had been shattered by gunfire. Police on Sunday asked residents to help them look for damage to homes and property that might provide more evidence.

Alisha Jaynes told KKTV she was at an ATM when she saw a man with a gun walking calmly down the street.

"They yelled, 'Put the gun down,' and he turned around, and that's when they shot at him a good 20 times," she said. "There was a lot of gunfire."

More than 50 people gathered for a candlelight vigil near the scene of the shooting Sunday night. Benjamin Broadbent, lead minister of the First Congregational Church of Colorado Springs urged the group to have compassion, even for the family of the gunman.