Phoenix Police Extend Landfill Search for Missing Mom; Boyfriend Charged With Murder

Christine Mustafa is presumed dead.
Silent Witness
Christine Mustafa is presumed dead.

Phoenix police have decided to extend the search for the body of missing Christine Mustafa in a municipal landfill by three weeks.

Investigators decided to continue the painstaking work, as the search entered its ninth, and final, planned week at the site near Gila Bend.

Mustafa, 34, vanished in May and her boyfriend, 38-year-old Robert John Interval, has been charged with her murder. He has pleaded not guilty and his lawyers plan to mount a defense on the grounds of insufficient evidence.

Last week, police sifted through another 2,100 tons of trash with bulldozers, rakes, and cadaver dogs, but still found nothing. They decided to continue looking, even though the odds of success are long and getting longer with every passing day.

click to enlarge Families of missing Christine Mustafa thank the volunteers searching for her at a landfill near Gila Bend. - SEAN HOLSTEGE
Families of missing Christine Mustafa thank the volunteers searching for her at a landfill near Gila Bend.
Sean Holstege
“It’s the right thing to do,” Police Sergeant Alan Pfohl said.

Police are not saying what the search is costing. Teams of 30 volunteers have been combing through a particular cell of the landfill since October 23.

They used GPS to pinpoint the exact cell to search within the massive landfill. Now, volunteers evacuate and sift through a mound of trash 14 feet deep, 500 feet long, and 120 feet wide. That’s larger than nine Olympic swimming pools.

The search is critical. Criminal investigators do not know for certain if Mustafa is dead, let alone how she died. Without her body, a weapon, or a confession, bringing her killer to justice is challenging.

“We can still prosecute the case. I am not able to discuss the details, but detectives feel they still have a good case,” Pfohl said.

Much of that case hinges on Interval’s behavior and statements at the time Mustafa disappeared. Police arrested Interval a month later. 

A search warrant affidavit remains the clearest picture of what drew detectives’ suspicion to him. It tells the following account.

The last time anybody saw Mustafa alive was when a coworker saw her leaving at around 3 p.m. on May 10. She didn’t show up to her job at Walgreens, her only absence in 11 years.

Mustafa’s family called Phoenix police and asked them to check on her. Police showed up to her house near North 20th Place and East Robin Lane that afternoon. They saw her gray Nissan Cube in the driveway, but heard no answer at the door.

Officers entered the empty house and found her purse, wallet, ID documents, and credit cards in plain sight. Her cellphone was wedged between the bathtub and toilet.

Interval showed up and told officers the couple had argued the night before, when he accused her of cheating on him. Mustafa had left early that morning.

click to enlarge Robert John Interval is charged with the murder of his missing girlfriend, Christine Mustafa. - MARICOPA COUNTY SHERIFF'S OFFICE
Robert John Interval is charged with the murder of his missing girlfriend, Christine Mustafa.
Maricopa County Sheriff's Office
Police asked Interval why she left her car. He said it had a flat tire. They noticed it did not.

Police returned the next morning to check on the feuding couple’s 8-month-old daughter.

Interval came to the door with a loaded .40 caliber Smith and Wesson handgun.

During the ensuing police search, Interval led them to his daughter’s room, where he said he used chemicals to kill the bedbugs in her mattress and bedsheets. He also had been cleaning the entry to the house — he said it was to get rid of a mess by the dog.

Police returned, this time with a search warrant.

Homicide detectives found traces of “blood-stained material” on the bedsheets. Using chemicals and a black light, they found more “blood or other biological material” on the walls.

Mustafa’s coworkers told detectives that Interval called frequently to accuse her of cheating. He threatened to kill her the day Mustafa vanished, police said in the court document.

Days after Mustafa disappeared, Interval’s sister flew in to comfort him. On May 15, she told police that he was “acting very paranoid,” and saying troubling things, such as “I took it too far.”

The sister told detectives she thought Interval killed Mustafa because she threatened to take the baby and leave him. The sister also told police that Interval planned to turn himself in to them.

On the day Mustafa vanished, Interval tried to sell the Nissan Cube on Facebook, plus a mattress and a trailer he used to haul debris for his tree-trimming business.

All of that made police suspicious, according to the affidavit they wrote to get a search warrant of Interval’s cellphone.

But the evidence remains circumstantial. Interval’s attorneys, from the public defender’s office, wrote in one court motion, “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.

The search continues.