On Thursday Erin Neathery, Mustafa's friend and a spokesperson for the family, held a press conference just hours after Phoenix police announced Interval's arrest.
According to Neathery, Mustafa was planning to leave Interval.
"He was consistently accusing her of cheating on him and constantly pushing at her," Neathery said. "So yes, they [her family] had hoped she would get out. Again, this is a common story for women trapped in relationships for whatever reason and sadly she didn't make it."
Neathery described Robert as being charismatic and outgoing — but she also said that he had a "dark side."
"He is quick to snap temper-wise," Neathery said. "I've seen him a couple of times; incidents that just flare up almost instantly — it was a bit of a red flag for me."
Neathery revealed that if Mustafa is found dead, this is the fourth daughter that her mother will have to bury.