DENVER ― Westminster police say a Colorado Springs man who allegedly shot two boys, their mother and a bystander Thursday afternoon, killing one of the boys, likely acted out of road rage.

Authorities arrested 23-year-old Jeremy John Webster without incident several hours after the shooting, which occurred in a parking lot outside a dental office in the northwestern Denver suburb of Westminster.

As of Friday morning, the woman, identified in a police affidavit as Megan Bigelow, 41, and her surviving son, age 8, were in critical condition at a local hospital, according to Westminster Police. Her other son was 13 years old.

Bigelow had a third son, a 12-year-old, with her at the time of the shooting. He fled and was not injured.

Jeremy John Webster, 23, allegedly shot four people, two of them children, outside Denver on Thursday. One of the boys, age 13, died. (Photo: Westminster Police)

“It appears as if this incident stemmed from a road rage,” Westminster Police Department investigator Cheri Spottke said in a press release late Friday afternoon, noting that Webster didn’t know any of the victims when he opened fire.

According to a copy of the affidavit obtained by 9News, Webster and Bigelow were involved in an altercation at a nearby intersection and he followed the family’s vehicle into the parking lot.

He shot her and the two children point-blank with a handgun multiple times, walked toward his car, then returned to the 13-year-old and fired again, the affidavit says.

Webster allegedly fired several shots at the bystander, John Gale, 40, from a distance after making eye contact with him as he and his 9-year-old daughter sat in their truck in the parking lot. He is expected to survive. She was unharmed.

Webster faces charges of first-degree murder after deliberation with intent, first-degree murder with extreme indifference, first-degree assault and criminal attempt to commit a class 1 felony.

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This article originally appeared on HuffPost.