Prosecutors face challenges in case of missing Christine Mustafa

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(Source: 3TV/CBS 5) (Source: 3TV/CBS 5)

Former Maricopa Superior Court judge and U.S. Attorney in Arizona, Mel McDonald, says convicting Robert Interval, Jr. in the disappearance of his live-in girlfriend, Christine Mustafa, will be difficult for prosecutors, but not impossible.

Mustafa disappeared May 10, 2017, after she missed a shift at work. Her phone, keys, and wallet were left at the North Phoenix home she shared with Interval. Her body has not been found.

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

Interval was arrested Thursday with police saying they were gathering new evidence every day pointing to him as a suspect.

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

“If you've got bloodstains and DNA connected to her, it's pretty tough sometimes to argue that she wasn't an object of violence,” says McDonald. 

Search warrant paperwork says investigators found evidence of blood in the home.  Documents also say Interval told police the two had been fighting over his suspicions she was cheating on him.

“If he's posted on Facebook, if he sent text messages, all of that stuff is devastating ammunition,” says McDonald. 

McDonald says defense attorneys will have a major advantage without the victim’s body.

“Maybe she was afraid and took off; maybe she had another boyfriend,” says McDonald.  He says defense attorneys will be free to speculate whether she’s dead and will capitalize on the lack of key testimony.

“In virtually every murder case you'll have the medical examiner testify to cause of death,” says McDonald.  “That’s going to be a conspicuous missing witness in the case.”

McDonald says it’s likely police were working with prosecutors before announcing Interval’s arrest.  He says it’s important that police arrested Interval now rather than later.

“Because you may never find a body and the case only gets weaker with the passage of time.”

Interval was in court Friday, where he was assigned $1 million cash bond.  He faces one count of first-degree murder.

[RELATED: $1 million bond set for boyfriend of missing Phoenix mother]

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