A significant development unfolded Friday night in the case of missing 84-year-old Nancy Guthrie, marking a “notable escalation” in the investigation in Arizona. Authorities are now swiftly working to gather neighborhood information and expedite crucial DNA analysis, as reported by a former FBI agent.

Following a promising lead, the Pima County SWAT team, in coordination with the FBI, executed a federal search warrant on a residence near Tucson, situated about two miles from Guthrie’s home. During this operation, three individuals were taken into custody.

Additionally, a fourth person was apprehended during a traffic stop at a Culver’s restaurant parking lot in Tucson. Law enforcement officials conducted a search of a gray Range Rover at the scene, which was subsequently towed away.

Jason Pack, who is a retired FBI supervisory special agent with over 20 years of experience, shared with Fox News Digital that the latest actions appear to be driven by “specific, actionable intelligence.”

Despite these developments, Pack emphasized that the core of the investigation is just beginning.

As searches and interviews continued into Friday night, Pack suggested that other teams of agents and analysts were likely already preparing to conduct a comprehensive neighborhood canvas around the searched location.

“They’ll be going door to door, looking to talk face to face with neighbors,” Pack said. “They want to identify patterns of life for each of the people detained. … It will help corroborate or dispute whatever those who were detained are telling agents right now. If someone says ‘I wasn’t home that night,’ a neighbor’s Ring camera might tell a different story. Investigators are building the box.”

Aside from canvassing the area, Pack said the most pressing concern is likely processing new evidence collected from at least two locations Friday night.

“DNA that doesn’t belong to Nancy Guthrie or anyone close to her has already been identified at her property. Gloves have been recovered. Now you’ve got whatever was inside that Range Rover that warranted agents draping it with a tarp before the cameras could see,” he said. “All of that evidence needs to get to a lab.”

Pima County Sheriff Chris Nanos recently defended his department’s use of a private Florida lab to process evidence in the case, telling Fox News earlier this week the FBI agreed it was best to continue with the contracted business rather than transfer the evidence to the FBI’s comprehensive crime lab in Quantico, Virginia.

However, Pack stressed the situation is a race against the clock.

“Here’s the question. Do they wait until Monday to commercially ship it to a private lab? In past high-profile cases, I’ve seen FBI aircraft used to immediately shuttle evidence to the FBI Laboratory at Quantico,” he said. 

“That eliminates days of waiting. In a case involving a vulnerable 84-year-old woman who is without her heart medication, where every hour matters, you don’t wait for FedEx on Monday morning.”

Pack reiterated that, in a time-sensitive case, authorities cannot afford to lose a weekend debating how to process evidence.

“That decision should have been made days ago. Which lab, which courier, what’s the turnaround?” he said. “If the FBI has the lead, Quantico is the logical answer, and I’d expect evidence to be wheels-up before the sun sets today.”

Authorities have not yet confirmed whether the newly obtained evidence will be flown to the private lab or Quantico or when it will take flight.