Updated

A suburban Utah police chief said Tuesday he's considering changes to the way stalking reports are handled amid questions about a 911 call a woman made days before her ex-boyfriend opened fire on a car full of children, killing her and her son.

But Sandy Police Chief Kevin Thacker defended the way his department deals with domestic violence complaints between couples who live together or are married, the definition under Utah law.

Dating couples like victim Memorez Rackley and shooter Jeremy Patterson, he said, do not fall into that category — so alleged victims in those type of situations are not offered the same services designed to protect them from abusers.

"This was a very unique case," Thacker said. "We haven't had one like this as far as I can remember."

Thacker also revealed that Rackley had started to fill out an application for a protective order to keep Patterson away from her after they broke up but did not finish it before she was killed last week in Sandy, a Salt Lake City suburb

Patterson, 32, confronted Rackley, 39, while she was walking her two sons home from their elementary school on June 6, police have said. An unidentified woman driving by with her daughter and two other children in her sports utility vehicle saw the argument and stopped to help.

Rackley and her two sons got inside and drove away, but Patterson followed them in his pickup truck and used it to ram the SUV several blocks away.

He then got out and opened fire. Rackley and her 6-year-old son, Jase, were killed. Her 11-year-old son, Myles, and the daughter of the driver were wounded. Patterson then fatally shot himself.

Rackley told police on June 3 her ex-boyfriend Patterson had sent her threatening text messages that included pictures of her children after following her and confronting her about the breakup.

Officers Sandy told Patterson to stop contacting her, advised her to stay with a friend and told her how to apply for a protective order. But because it was not considered a domestic violence case, they did not ask a series of questions designed to determine whether the case could turn deadly, police have said.

Doing so would likely have flagged the case as high-risk and put her in touch with a social worker to help her navigate the court system, said Utah Domestic Violence Coalition executive director Jenn Oxborrow.

Thacker said he's considering whether the department has the resources to offer those services to dating couples, and expected to decide in the next month.

State officials are pushing to revise state law on domestic violence to include dating couples, said Ned Searle, Office on Domestic and Sexual Violence.

Dating couples make up about half of people who report relationship crimes, so treating them differently from wedded or living-together couples is risky, experts and advocates say.

Rackley's 911 call also was not connected to a second 911 call that came into the suburb of Draper that borders Sandy just hours before the shooting on June 6. An unidentified person in that call who knew Patterson told police he had said wanted to kill her.