(NewsNation) ⁠— Earlier this month, 18-year-old Naomi Irion went missing and her brother contacted authorities. But, in the weeks that followed, Irion’s family was briefly left to do their own investigating, sparking a nationwide, recurring debate: How should police respond when an adult is reported missing?

In the U.S., local police response to missing adult reports can be complicated. Unlike children, adults have a legal right to go missing, sometimes limiting the investigative powers of law enforcement, according to a 2019 report by the Congressional Research Service. In domestic violence situations, for example, an adult victim has the right to leave without a trace.

The powers that law enforcement does have are further strained by limited resources, said Jay Groob, president of American Investigative Services, Inc.

“They can’t just react on any call,” Groob said. “There has to be some foundation for them to react.”

In those situations, private investigators can often compile information that could later assist police once a proper investigation is underway, Groob said. That’s particularly important since the first 24-48 hours a person is missing are “crucial,” he said.

“They’re critical. You have to act immediately once you know they’re missing,” Groob said.

Irion’s brother, Casey Valley, placed calls to local hospitals and jails when he discovered that his sister never returned from her shift at Panasonic in Fernley, Nevada. When those efforts were unsuccessful, Valley tried to file a missing person report on his sister on March 13.

“We didn’t know what was going on. So I called the police and tried to file a missing persons report,” Valley told NewsNation Monday. “The deputy never came. He did call me and he basically said, You know, this isn’t enough to file a missing persons report on an adult, and said to call him again tomorrow, on (March 14).”

Such a response from law enforcement isn’t uncommon, Groob said. Information suggesting the person is in danger often elicits swifter action from police, he added.

Valley took it upon himself to retrieve surveillance footage from the Walmart parking lot where Irion would have been waiting for a shuttle to take her to work. The video showed a man whom Irion’s family didn’t recognize enter the woman’s car and drive away before she caught her shuttle. By Monday, Irion had been missing for two days. Police discovered her remains on Tuesday ⁠— more than two weeks after her disappearance — in Churchill County, Nevada. Her death is being investigated as a homicide.

“That’s really bothersome to me when I read all about that — that it was actually the family that had to go in and pull the video and figure out what part of the parking lot she was in and that they weren’t taken seriously by law enforcement,” former FBI Agent Jennifer Coffindaffer told NewsNation on Wednesday.

“That’s something that’s going to have to change, and I think that the new spotlight on these cases, that really Gabby Petitio’s case instigated, I’m hoping that we’re going to see a better reaction from these departments to take these cases seriously,” Coffindaffer said.

The real number of missing adults in the U.S. is unknown and what is known is underreported, according to the National Institute of Justice.

As of Dec. 31, 2020, children under the age of 18 accounted for 34% of acting missing person records in the National Crime Information Center’s Missing Person and Unidentified Person system. They accounted for 43% when a juvenile was defined as anyone younger than 21 years old.

When a person is reported missing, law enforcement has the option of entering that person’s DNA and case details into a handful of federally managed databases. Members of the public can also review cases and enter data that is then vetted by law enforcement.

Although law enforcement is encouraged to upload missing person case information to those systems, few states require it.

In Groob’s experience, however, a delayed police response to a report of a missing adult is often the product of limited resources and legal restrictions, not apathy, he said.

“That’s why they’re handcuffed — law enforcement is,” Groob said.

The Lyon County Sheriff’s Department, which handled Irion’s case, did not respond to NewsNation’s requests for an interview.

Prosecutors have charged Fallon, Nevada, man Troy Driver with murder Friday in connection with Irion’s disappearance.

NewsNation correspondent Brian Entin contributed to this report.