Tucson man sentenced for straw purchase of part for AR-15 used in deadly ambush of Pima constable, 2 others

A Tucson man was sentenced Friday to three years probation and time served behind bars for lying to federal officials about his purchase of firearm component for an AR-15 rifle later used to ambush and kill Pima County Constable Deborah Martinez and two others at a North Side apartment complex last August.

Josue Lopez Quintana, 25, was indicted and charged last September with lying to federal agents and falsely filling out a federal form when he purchased the part on behalf of Gavin Lee Stansell.

On Aug. 25, 2022 Stansell used a Sharps Bros MFG model Livewire 5.56mm rifle to fatally shoot Martinez, along with 28-year-old Angela Fox-Heath, as they attempted to serve an eviction notice on him at Lind Commons apartments.

After killing both women, the gunman broke through the wall of a closet in his apartment and entered a neighbor's apartment, where he found 25-year-old Elijah Miranda, shooting and killing him. Miranda, a visitor, was staying in the apartment to escape from the summer heat. The resident of that apartment, who was not at home, had earlier been threatened by the shooter.

Stansell then fatally turned the gun on himself.

Following the shooting, investigators with the Bureau of Alcohol, Tobacco, Firearms and Explosives linked the part of the weapon used by Stansell to Lopez Quintana. However, he lied to federal agents about the purchase before later recanting and acknowledging his role in procuring a weapon used to murder three people.

In November, Lopez Quintana pleaded guilty to a single charge of lying to federal investigators.

Prosecutors sought time -served and three years of probation, telling the court Lopez Quintana's "false statement to law enforcement was material" and "affected the ability of ATF to provide an accurate report."  However, the sentence is "sufficient, but not greater than necessary, to reflect the seriousness of the offense of conviction, promote respect for the law, provide punishment for the offense, and afford adequate deterrence," wrote Jane Westby, a federal prosecutor.

"While there is no excuse for defendant’s false statement to law enforcement, there is no evidence that defendant knew" the gunman's intent. "Furthermore, defendant quickly accepted responsibility and plead guilty shortly after he was indicted," she wrote.

During a hearing Friday, Lopez Quintana stood with attorney James Smith and agreed to the guilty plea, telling U.S. District Judge Jennifer G. Zipps he "made a mistake" when he purchased part of the weapon.

"Tell me what you learned," said Zipps. Lopez Quintana looked pained and rubbed a small x-shaped cross tattooed on his cheek before he telling Zipps he learned he shouldn't have lied to federal agents as they sought to connect the weapon to his purchase. "I learned I should do the right thing, and not lie, or just sign anything."

"I appreciate your remorse, but I can't help but comment on how your actions lead to a unfortunate result," said Zipps. She noted he purchased the part as a favor and was paid back rather than seeking a profit for the purchase.

Zipps agreed with prosecutors and sentenced Lopez Quintana to three years probation, and fined him $3,000, which will be paid over the next 3 years.

Gun part linked to shooting deaths

Following the mass shooting, ATF agents linked the weapon used by the gunman to Lopez Quintana, tracing the serial number on the rifle's lower receiver. The lower receiver houses internal components, including the firing mechanism, and is what federal officials classify as the "firearm" itself for AR-15-style semi-automatic rifles. Because this part is integral to making the firearm, it is controlled more strictly than other AR-15 parts, and unlike dozens of other components, buying one requires filing out a federal form.

When Lopez Quintana bought the part, he filled out such a form, known as a ATF Form 4473, and indicated he was "the actual buyer" of the lower receiver. On Aug. 26, ATF agents along with special agents with Homeland Security Investigations, a part of Immigration and Customs Enforcement, interviewed Lopez Quintana. He lied and told the agents he bought the lower receiver to "build an 'AR' for himself." He also said he later sold the lower receiver to "his friend 'Gavin' in 'April or May,'" according to court documents.

Agents reviewed his cellphone records, and found that Stansell asked Lopez Quintana to buy the part for him online in November 2021. Lopez Quintana bought the lower receiver for him and had it delivered to a gun dealer in Tucson. He told agents that Stansell explained he needed help because he had an out-of-state identification card. After the purchase, Stansell paid Lopez Quintana back.

On Aug. 30, Lopez Quintana told agents he "lied to them to minimize his involvement."

Before buying the part, Stansell had been trying to 3-D print his own gun parts, sources told the Sentinel.

Incident unfolds

On Thursday, Aug. 25, dispatchers received a call around 11:13 a.m. that shots had been fired at at Lind Commons, an apartment complex in the 3400 block of East Lind Road, on Tucson's North Side, said Sgt. Richard Gradillas, a spokesman for Tucson Police Department

TPD officers arrived and found Fox-Heath dead in the courtyard with "obvious signs of gunshot trauma," he said.

Gradillas said police believe Stansell opened fire as Martinez and Fox-Heath went to contact him, fatally wounding Fox-Heath. Martinez was found inside the apartment by members of TPD's SWAT team, who arrived after police realized they couldn't find the constable and believed she was inside the apartment with the gunman.

During the incident, residents of the apartment complex were evacuated from their homes and placed aboard a Sun Tran bus just a few blocks away.

Police entered the apartment and found Martinez inside, dead from gunshot wounds. Officers later found the shooter dead in his apartment, and Miranda dead in the apartment next door.

Court records show that an eviction order was to be served on Stansell. A hearing in that case was held the Monday before the incident, with the order issued the next day, Pima County Justice Court records showed. According to a court filing by the landlord's attorney, Stansell had threatened another resident of the apartment complex with a gun.

Local online court records showed no prior criminal offenses by Stansell, but he has a more lengthy criminal record in Hawaii.

The complex, previously known as Palo Verde Terrace, has been the scene of previous violent incidents, including a January 2022 drug-related shooting that left a man hospitalized. Seventeen 9mm bullet casings were found at the scene of that incident. And, sources have told the Sentinel that the apartment complex has been the site of at least several overdose deaths in recent years.

Martinez was appointed as a constable, responsible for serving court papers such as evictions and orders of protection, in March 2022, filling a vacancy left by the resignation of Constable Kristen Randall. Martinez was seeking to continue in her post by being elected in her Midtown precinct, despite being under investigation by the Arizona Constable Ethics, Standards and Training Board for allegations of potential felony fraud, forgery, perjury and tampering with public records.

A Tucson native and Pueblo High School graduate, Martinez retired from U.S. Army intelligence after multiple tours in Afghanistan and serving for 16 years.

Martinez was survived by her husband, Gabriel Garibay, and 22-year-old daughter Ryane Martinez. On Sept. 1, a Catholic mass was held in Martinez's honor at St. Augustine Cathedral in downtown Tucson.