Retired FBI agent urges rapid DNA testing in Guthrie case: 'You don’t wait for FedEx on Monday morning'

An evident large-scale cognition Friday nighttime tied to the disappearance of 84-year-old Nancy Guthrie marks a "significant escalation" successful the Arizona case, with investigators present racing to canvas neighborhoods and fast-track captious DNA evidence, according to a retired FBI agent.

Acting connected a lead, the Pima County SWAT squad and the FBI connected Friday executed a national hunt warrant astatine a Tucson-area location astir 2 miles from Guthrie's home, detaining 3 people.

A 4th idiosyncratic was detained successful transportation to the warrant pursuing a postulation halt successful a Culver's edifice parking batch successful Tucson, and a grey Range Rover was searched and towed from the parking lot.

Jason Pack, a retired FBI supervisory peculiar cause with much than 2 decades of service, told Fox News Digital the developments person the "hallmarks of agents acting connected specific, actionable intelligence."

A Pima County Sheriff's lawman inspects a Range Rover pursuing a postulation halt wherever 1 antheral was detained successful Tucson, Ariz, Friday, successful narration to the Nancy Guthrie disappearance case. (Kat Ramirez for Fox News Digital)

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However, Pack noted the existent investigative enactment is conscionable getting started.

While the searches and interviews were ongoing Friday night, Pack said different teams of agents and analysts were apt already readying a afloat vicinity canvas astir the determination that was searched.

"They’ll beryllium going doorway to door, looking to speech look to look with neighbors," Pack said. "They privation to place patterns of beingness for each of the radical detained. ... It volition assistance corroborate oregon quality immoderate those who were detained are telling agents close now. If idiosyncratic says 'I wasn’t location that night,' a neighbor’s Ring camera mightiness archer a antithetic story. Investigators are gathering the box."

The Pima County Sheriff's Department conducts a instrumentality enforcement cognition astatine the intersection of Camino de Michael and East Orange Grove Road successful Tucson, Ariz. (DWS for Fox News Digital)

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Aside from canvassing the area, Pack said the astir pressing interest is apt processing caller grounds collected from astatine slightest 2 scenes Friday night.

"DNA that doesn’t beryllium to Nancy Guthrie oregon anyone adjacent to her has already been identified astatine her property. Gloves person been recovered. Now you’ve got immoderate was wrong that Range Rover that warranted agents draping it with a tarp earlier the cameras could see," helium said. "All of that grounds needs to get to a lab."

Pima County Sheriff Chris Nanos precocious defended his department's usage of a backstage Florida laboratory to process grounds successful the case, telling Fox News earlier this week the FBI agreed it was champion to proceed with the contracted concern alternatively than transportation the grounds to the FBI's broad transgression laboratory successful Quantico, Virginia.

A antheral is detained pursuing a postulation halt successful Tucson, Ariz., Friday, successful narration to the Nancy Guthrie disappearance case. (Kat Ramirez for Fox News Digital)

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However, Pack stressed the concern is simply a contention against the clock.

"Here’s the question. Do they hold until Monday to commercially vessel it to a backstage lab? In past high-profile cases, I’ve seen FBI craft utilized to instantly shuttle grounds to the FBI Laboratory astatine Quantico," helium said. "That eliminates days of waiting. In a lawsuit involving a susceptible 84-year-old pistillate who is without her bosom medication, wherever each hr matters, you don’t hold for FedEx connected Monday morning."

Pack reiterated that successful a time-sensitive case, authorities cannot spend to suffer a play debating however to process evidence.

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"That determination should person been made days ago. Which lab, which courier, what’s the turnaround," helium said. "If the FBI has the lead, Quantico is the logical answer, and I’d expect grounds to beryllium wheels-up earlier the prima sets today."

Authorities person not yet confirmed if the recently obtained grounds volition beryllium flown to the backstage laboratory oregon Quantico, oregon erstwhile it volition instrumentality flight.