PHOENIX — A jury has found Robert Interval guilty of murdering his girlfriend and mother of his child, Christine Mustafa.
Interval, 37, was tried on one count of premeditated first-degree murder in the presumed death of 34-year-old Mustafa, however, the jury was unable to agree on that charge. Instead, the jury found Interval guilty of the lesser offense of second-degree murder when they delivered the verdict Tuesday morning.
Mustafa was last seen May 10, 2017. She didn't show up for work the next day.
Police believe Interval killed Mustafa and then dumped her body in City of Phoenix SR 85 Landfill. Despite an extensive weekslong search through 1,600 tons of landfill debris, Mustafa's body was not found.
Interval's trial in the Maricopa County Superior Court began in February of this year.
During the trial, prosecutors described Interval as a boyfriend constantly paranoid Mustafa was cheating on him. Officials say Mustafa contacted the Phoenix Police Department the day before she vanished and asked about how to get a restraining order against Interval.
Prosecutors also said Interval bought mattress covers the day Mustafa disappeared and was seen outside a trash transfer facility later that day.
Mustafa's sister, Linda Donaldson, told 12 News after the verdict was read that justice was not served today. She said her sister's killer will be out in a matter of years while her sister will still be gone.
Courtroom spectators Tuesday gasped when the jury verdict was read acquitting Interval of first-degree murder before the conviction of the lesser offense was read.
Interval now faces up to 29 years in prison for the conviction. His sentencing is currently scheduled for June 7.
The Associated Press contributed to this report.