PHOENIX (AP/FOX 10) -- Courtroom spectators gasped when a jury verdict acquitting a Phoenix man of first-degree murder was read Tuesday, before a second verdict convicted Robert John Interval of second-degree murder in the death of his girlfriend, whose body has never been found.
"We the jury do find the defendant Robert John Interval as count one first-degree murder, victim Christine Mustafa, not guilty," said the jury forewoman.
Mustafa, 34, disappeared in May 2017. Her car was still parked at home where her wallet and purse were on the bathroom floor.
Defense attorney Jamie Jackson said during the trial there was no proof that Mustafa is dead, suggesting she may have left Interval for a fresh start.
Police said in court documents that there were indications of possible blood stains on bedding and indications of blood or other biological material on walls.
During the trial, the prosecution said the 39-year-old Interval made incriminating statements in texts, bought mattress covers the day Mustafa disappeared and was seen outside a trash transfer facility later that day.
Authorities searched for her body at a Phoenix landfill for 12 weeks. Police examined 21,500 tons (19,504 metric tons) of material during the landfill search, which involved approximately 280 officers from 12 city, state and federal law enforcement agencies and cost nearly $1.5 million, including spending for excavation and other equipment and for overtime.
Her remains were never found, but after the search ended in December 2017, police said there still was enough evidence to win a conviction.
Mustafa's sister Linda Donaldson says she hopes the judge isn't lenient with his ruling.
"I'm hoping that the judge gives him the max, I really do."
Prosecutors say Mustafa was a reliable person who made and kept plans and never failed to show up for a shift in her 13 years of working for a drug store chain. Mustafa's family testified that she was a responsible, compassionate and loving mother who cared deeply for her children.
Police say Mustafa had plans to leave Interval.
Donaldson says her sister's death leaves them with an emptiness that may never go away.
"I don't think we'll ever have closure. I think the closest to closure would've been first-degree conviction... As closest to closure as you can get. Where do you go, to have a memorial, the landfill? A place where trash is disposed, I mean that's unrealistic."
Sentencing for Interval, who faces up to 29 years in prison for the conviction, is scheduled for June 7.