Update, April 16, 2019: Robert John Interval was convicted today in Maricopa County Superior Court for second-degree murder even though the body of his missing girlfriend, 34-year-old Christine Mustafa, was never found despite a massive landfill search in 2017 by Phoenix police that cost almost $1.5 million.
Sentencing for Interval is scheduled for June.
The original story, published on November 3, 2017, begins here:
The search for 34-year-old Christine Mustafa began six months ago at a north Phoenix house and may end at a landfill near Gila Bend where hope can take the shape of a bone fragment.
Phoenix police Friday wrapped up their second week combing through a mountain of trash with bulldozers, rakes, and cadaver dogs.
Teams of 30 or so volunteers in biohazard moonsuits have been picking over one cell of the city landfill, eight or nine hours a day, Monday through Friday. It’s meticulous, physically demanding, and mentally draining work. The crews clear about 300 to 500 tons a day, Phoenix Police Sergeant Alan Pfohl said.
His boss, Police Chief Jeri Williams, was there to express gratitude for the effort and hope that it will pay off, with seven scheduled weeks to go.
Meanwhile, Mustafa’s boyfriend, Robert John Interval, 38, is sitting in a Maricopa County jail cell awaiting trial and news of the case.
Police arrested him on June 8, about a month after Mustafa’s vanishing, and held him on suspicion of murdering his girlfriend.
Nine days later, a Maricopa County grand jury indicted him for first-degree murder. He pleaded not guilty and was held on $1 million bond.
His attorneys, from the public defender’s office, filed motions to release him and lower the bond to $100,000, arguing, “The weight of evidence against the defendant is tenuous.”
“The state is still continuing to investigate in this case and is currently following up on those leads. The investigation is still in the beginning phases and it is difficult to determine how long it will last,” defense lawyers wrote.
In a later filing, Interval’s lawyers told the court the defense would be insufficient evidence. The discovery of a body in the City of Phoenix SR 85 Landfill would mark a major breakthrough for prosecutors.
A hearing to consider his release is set for November 27.
Much of the record in Interval’s case remains sealed, but an affidavit to gain a search warrant most clearly spells out the reasons Phoenix detectives grew suspicious of Interval.
Mustafa was last seen in the area of North 20th Place and East Robin Lane on May 10 around 3 p.m. She was last heard from in the early hours the next day, police said at the time, asking for public help in finding her.
Mustafa was last seen by a coworker leaving work. She spoke to her sister later that night.
The next day she failed to show up to work at Walgreens for the first time in 11 years, according to the Phoenix detective’s sworn statement.
That day, May 11, her family called Phoenix police and asked them to check on her well-being. Police showed up late in the afternoon, saw Mustafa’s gray Nissan Cube in the driveway, but heard no answer at the door.
Fearing for her safety, and “believing there was a standard of exigency,” as police put it, officers picked the lock and entered the house.
It was empty, but police found her purse, wallet, ID documents, and credit cards in plain sight. They found her cellphone between the bathtub and toilet, according to the five-page statement.
During the search, Interval showed up. He told officers the couple had argued the night before when he confronted her with his suspicion that she’d been cheating on him. He went on to tell police that Mustafa had left early that morning after a similar row, but there was never anything physical.
Police, they told the court, asked why she left her car, to which he said it had a flat tire. It did not.
The next day, May 12, police returned to the house in the late morning to check on the well-being of the feuding couple’s shared 8-month-old daughter.
This time, Interval answered the door with a loaded .40 caliber Smith and Wesson handgun.
Police began a new search of the house, and he told investigators he was cleaning the entryway and front room because his dog had chosen to vacate his bowels and bladder there.
He led them to his daughter’s room. He told police he’d used chemicals to kill the bedbugs in her mattress and bedsheets.
After turning the baby over to temporary protective custody, police came back a third time, now with homicide detectives and a search warrant. They found traces of “blood-stained material” on the bedsheets, and using chemicals and a black light, more “blood or other biological material” on the walls, according court records.
With their suspicions already aroused by the forensics and by Interval’s remarks, police expressed other reasons they focused on him.
Mustafa’s coworkers had told detectives that Interval would “constantly call Christine at work and accuse her of cheating.” One recounted a call on the last day she was seen there, in which Interval renewed the accusation, “then threatened to kill her,” the court document said.
Interval’s sister flew in from Ohio to comfort him. On May 15, she told police that he was “acting very paranoid” and making troubling statements, police swore.
In one, he confided, “I took it too far.”
In another, “I can never un-see the things I saw.”
The sister told detectives she thought Interval killed Mustafa because the last night she was seen alive she threatened to take the baby and leave him, according to the police statement. Interval later told his sister, she told police, that he planned to turn himself in. He didn’t say why.
Also, the day Mustafa disappeared, Interval posted for sale on Facebook the Nissan Cube, a mattress, and a trailer he used to haul debris for his tree-trimming business.
When police caught up to Interval on May 16 at his father’s house, he was still carrying the Smith and Wesson and declined to answer questions. After his arrest, police seized his cellphone, but couldn’t access it. They got a search warrant to compel Interval to unlock the code.
No other court records detail what investigators think they have on their suspect. And they still have no body and no cause of death.
Williams told reporters Friday that no effort was too much to bring peace and justice to Mustafa’s family. Behind her, a banner from that family thanking the searchers fluttered in the steady desert breeze on the chain-link entry gate to the landfill.
“We have law enforcement trying to exhaust every effort possible in locating Christine Mustafa,” Williams said.
She refused to say how much the search was costing.
“It’s a low probability, but do you put a price tag on it? No. You don’t put a price tag and you don’t put a time tag on it. It’s the right thing to do,” Williams said.
The undertaking is enormous.
Volunteers have to excavate, then sift through a mound of trash 14 feet deep, 500 feet long, and 120 feet wide. That’s the equivalent volume of more than nine Olympic swimming pools.
They used GPS to pinpoint the exact cell to search within the massive landfill.
“Each piece of equipment at the landfill is equipped with GPS, so we were able to see not only where the trash was dumped, but where it was pushed by the bulldozers. We then took those coordinates and used a total station to go out to the site and map the search area,” Pfohl explained.
We Believe Local Journalism is Critical to the Life of a City
Engaging with our readers is essential to Phoenix New Times's mission. Make a financial contribution or sign up for a newsletter, and help us keep telling Phoenix's stories with no paywalls.
Support Our Journalism
Any time volunteers or cadaver dogs spot something promising, the crews stop, photograph the scene, and send the photographs to the Maricopa Medical Examiner’s Office where forensic anthropologist Dr. Laura Fulginiti advises them what they have.
It’s work that brings small hopes and big disappointments daily.
Pfohl said the work is “going well.” Crews cleared nearly 1,400 tons of rubbish last week and a little more than 1,300 this week. Crews are looking for human remains, rather than any specific shred of evidence, he said.
“We are here for hope,” Williams said. “I am so hopeful. I am so prayerful. I am mom. I am a wife. Christine was a mom. ... Who wouldn’t want to continue searching for somebody like that?”