Police say they are recommending a first-degree murder charge be filed against the ex-boyfriend of a 19-year-old Phoenix woman who was found dead a month after she vanished.

Sgt. Vince Lewis of the Phoenix Police Department said Tuesday afternoon that investigators have developed probable cause linking Jon Christopher Clark to the death of Kiera Bergman.

According to court documents, Clark picked Bergman up from work early on the last day anyone saw her alive. Bergman's body was found wearing the same clothes she had on when Clark picked her up.

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Police believe that Clark was sending text messages to her roommate's phone and his own phone to make it seem that Bergman was still alive.

Police say the text messages sent from her phone to Clark saying she left and was allowing him to have some money from her bank account were actually made from inside Bergman's apartment while on her WiFi router.

Documents state that Clark's statements and multiple witness accounts didn't match.

Clark made his first court appearance on one count of first-degree murder, one count of improper removal of a body and one count of evidence tampering. A cash-only bond was set at $1 million.

Clark, 23, was already in jail on unrelated charges of aggravated identity theft and forgery. He was arrested about two weeks after Bergman disappeared but at the time, investigators did not have anything to connect him to her case.

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

[MUGSHOT: Jon Christopher Clark]

Bergman was last seen alive on Aug. 4 at her Phoenix apartment in the area of 51st Avenue and Thunderbird Road.

Her body was found on Sept. 3 in a desert area near State Route 85 in Buckeye. It wasn't clear how long her body had been there or how she died.

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[READ MORE: Police say body found near SR 85 is that of young Phoenix woman missing for a month]

Bergman's parents said their daughter moved to Phoenix from San Diego earlier this year to be with Clark.

They also said that she changed after her move, seeming to have lost her spirit.

Bergman and Clark reportedly broke up not long before she disappeared.

Now police believe Clark is responsible for her murder.

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[READ MORE: Parents of missing Phoenix woman found dead 'want justice for her']

While law-enforcement agencies make charging recommendations in their cases, it is always up to the Maricopa County Attorney's Office to make the decisions and take action.

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