Ex-boyfriend indicted for allegedly murdering Avondale teen, attempting to kill her mother

Emilio Rivera, 18, was indicted in late November for allegedly killing his ex-girlfriend, 17-year-old Rhiana Kemplin, and attempting to kill her mother.

BY JEFF VINTON

Dec 4, 2025, 10:23 AM Updated: 10:27 am

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PHOENIX — A West Valley teen has been indicted for allegedly killing his ex-girlfriend and attempting to kill her mother, authorities announced Thursday.

Emilio Rivera, 18, was formally charged on Nov. 25 with first-degree murder, attempted second-degree murder and criminal damage in connection with the Nov. 8 shooting death of 17-year-old Rhiana Kemplin in Avondale, according to the Maricopa County Attorney’s Office (MCAO).

Emilio Rivera is accused of murdering his ex-girlfriend, 17-year-old Rhiana Kemplin, on Nov. 8. (Photo: MCSO)

Rivera is currently being held on a $1 million cash bond, according to prosecutors. His trial is scheduled to begin in July 2026.

Why was ex-boyfriend indicted for murder of Avondale teen?

On the morning of the crime, the Avondale Police Department responded to reports of a shooting at an apartment complex near Rancho Santa Fe Boulevard and McDowell Road.

When officers arrived, they found Kemplin, who had been shot. She was taken to a nearby hospital and later died.

Rivera, who had been in a relationship with Kemplin, was arrested at a home in Buckeye on Nov. 14.

According to MCAO, Rivera allegedly shot Kemplin while she was sleeping and then went into her mother’s bedroom and tried to shoot her, but his gun jammed.

He also allegedly slashed the tires of several cars, including Kemplin’s, in the apartment complex’s parking lot, prosecutors added.