$1 million bond set for boyfriend of missing Phoenix mother

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A $1 million bond has been set for Robert John Interval. (Source: Maricopa County Superior Court) A $1 million bond has been set for Robert John Interval. (Source: Maricopa County Superior Court)
Missing Christine Mustafa (Source: 3TV/CBS 5) Missing Christine Mustafa (Source: 3TV/CBS 5)
PHOENIX (3TV/CBS 5) -

A $1 million bond has been set for a Phoenix man arrested on suspicion of first-degree murder in connection with his missing girlfriend Christine Mustafa.

Robert John Interval didn't have a lawyer at his initial court appearance Friday.

[VIDEO: Robert Interval initial appearance in court]

Maricopa County prosecutors sought a high bond amount, saying the 37-year-old Interval is a flight risk.

Phoenix police say detectives developed probable cause to arrest Interval in the case Thursday, although the body of 34-year-old Mustafa has yet to be located.

[RELATED: Police arrest boyfriend in missing Phoenix woman case]

She was last seen on the afternoon of May 10 and failed to show up for her scheduled work shift the next morning.

Mustafa's family asked police to check on her welfare and they went to the home she shares with Interval.

When police went to her home, there was no answer. Police said Interval arrived at the home and told them Mustafa had left for work and was walking there.

On May 16, police searched the house and reportedly found her wallet, cell phone and car. They also reportedly discovered bedding that appeared to have small amounts of blood on it.

Investigators also took Interval's handgun and cell phone, documents said.

A search warrant says the boyfriend explained to investigators that the couple “got into a verbal argument on the night of May 10 over his beliefs that she was cheating on him.”

The documents describe a conversation one of Mustafa’s coworkers had with investigators telling them the boyfriend had even threatened to kill Mustafa.

Mustafa also disappeared without her 8-month-old baby.

[ORIGINAL STORY: Phoenix police ask for help finding missing Phoenix mother]

Even though police have made an arrest, they're still looking for more information. If you have any, call Phoenix Police or call Silent Witness at either 480-WITNESS (948-6377) or 1-800-343-TIPS (8477). Spanish speakers may call 480-TESTIGO (837-8446). (Click or tap phone number to call from this story on your mobile device.)

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Copyright 2017 KPHO/KTVK (KPHO Broadcasting Corporation). All rights reserved. The Associated Press contributed to this report.news