PHOENIX — The Maricopa County Superior Court says the jury has reached a verdict in the murder trial of Robert Interval and will deliver the verdict Tuesday morning. 

Interval, 37, was tried on one count of premeditated first-degree murder in the presumed death of 34-year-old Christine Mustafa. His trial started in February of this year.

Mustafa was last seen May 10, 2017, and didn't show up for work the next day. She and Interval shared a child.

PREVIOUSLY: Murder trial begins for the man police say killed Christine Mustafa

Police believe Interval killed Mustafa and then dumped her body in City of Phoenix SR 85 Landfill. Despite a thorough nine-week search through 1,600 tons of landfill debris, Mustafa's body was not found. 

READ: Phoenix police turn to GPS, cadaver dogs in landfill search for Christine Mustafa

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 in May 2017 and was seen outside a trash transfer facility later that day.

The case was left to the jury late last week. The court says the jury will announce the verdict Tuesday at 10:30 a.m.

The Associated Press contributed to this report.