New court documents show a search warrant served for the cell phones of a Valley missing woman, her ex-boyfriend and an apartment router led to his arrest.

Kiera Bergman went missing Aug. 4. Someone on a bike found her dead a month later. Her decomposed body was dumped in a bush in Buckeye.

[ORIGINAL STORY: Parents of missing 19-year-old Kiera Bergman desperately searching for answers]

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Tuesday, police recommended murder charges against her on-again, off-again boyfriend Jon Christopher Clark who had been living with Bergman and their female roommate.

The roommate, according to court documents, said while at work the morning of Aug. 4th, she and Kiera "had a discussion about the possibility Kiera was pregnant."

[RELATED: Police believe ex-boyfriend killed missing Phoenix woman found dead]

The roommate described Clark as "controlling and manipulative."

The day before Bergman went missing, court documents revealed Bergman and Clark were arguing because Bergman wanted him to move out.

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Clark and Bergman didn't have cell phone service. Both could only send messages when connected to Wi-Fi.

Clark claimed he saw Bergman leave the apartment on Aug. 4 with her phone after an argument.

[RELATED: Police: Body found near SR 85 is that of young Phoenix woman missing for a month]

However, police think Clark actually had Bergman's phone while she was missing and pretended to be her by sending messages to himself and their roommate from her phone.

According to the documents, "All text communications from Jon's cell phone during the same time frame was found to have been through the router in Kiera's apartment."

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[MUGSHOT: Jon Christopher Clark]

One of the text messages was to Bergman's female roommate saying, "Girl, my phone is about to die but I'm fuc#$*# done with Jon. I met this guy a couple days ago when I went to the store and I asked him to come pick me up so I'm just chilling with him at his house smoking. I'll call you when I get a charger, and make sure Jon leaves."

Another text showed Clark asking Bergman for money which she apparently approved via text. Clark had access to Bergman's purse which she left behind. According to court documents, he used her bank cards to gas up her car, withdraw money from an ATM and buy items at Walmart totally more than $500.

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[RELATED: 'Vigil of Hope' held for missing 19-year-old]

Bill Kalaf, a retired information technology expert for police, has more than 20 years of experience helping detectives use technology to find evidence.

Even though he's not helping to investigate this case, he provided perspective on why police were likely not able to immediately arrest Clark in connection to Bergman's death.

[RELATED: Police arrest former boyfriend of missing woman for identity theft, forgery]

"It takes time to build the probable cause to get the warrant. Once they get the warrant, they can pick up a cell phone and that's because of privacy rules."

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He said it doesn't make sense why Bergman, if apparently missing with her phone on her, would be texting from her own apartment.

He explained Wi-Fi router in this case key to proving Bergman's phone was being used inside her apartment when she was gone, because the router logs when a device is connected, who the device belongs to and when it's being used.

"There's a disagreement between what the subject has said, what's actually recorded on the phones, and what's recorded on the routers," said Kalaf.

Court documents also revealed Clark didn't have a job and wasn't paying rent.

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