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Man admits to murdering 2 women and an unborn child after matching prints found on ‘Cheetos bag and Coke bottle’ left at the scene

Juan Antonio Arreola-Murillo, Sonja Mejia, and Damilla Castillo (Salt Lake County District Attorney's Office)

Juan Antonio Arreola-Murillo, Sonja Mejia, and Damilla Castillo (Salt Lake County District Attorney’s Office)

A 42-year-old man will likely spend the rest of his life in prison after admitting to killing two women and an unborn child in a series of slayings dating back more than 15 years.

Juan Antonio Arreola-Murillo formally pleaded guilty in Utah on Monday to three first-degree felony counts of aggravated murder in the 2006 killings of 29-year-old Sonia Mejia and her unborn daughter, as well as the 2008 death of 57-year-old Damiana Castillo.

The murders took place on the same date — Feb. 9 — exactly two years apart. He will face sentencing on Aug. 10.

According to a press release from the Salt Lake County District Attorney’s Office, Arreola-Murillo was in the U.S. illegally and deported back to Mexico by authorities eight months after Castillo was killed, but before he was identified as a suspect in her murder.

It wasn’t until 2016 that investigators were able to match fingerprints recovered from both of the crime scenes with Arreola-Murillo. He was charged with all three counts of murder the following year, but he wasn’t able to face those charges in the U.S. at the time: he had been convicted in Mexico for a series of aggravated robberies and was serving time in prison there.

In January 2022, after completing his sentence, Arreola-Murillo was released from detention and extradited back to Utah to face the murder charges.

“Our office mourns the losses of Damiana Castillo, Sonia Mejia and her unborn child,” District Attorney Sim Gill said in a statement following the plea hearing. “While perfect justice would mean that these three individuals would still be with us today, we hope that these guilty pleas can bring a semblance of justice and closure for these families. We would like to acknowledge Unified Police Department, West Valley City Police Department, and our prosecutors for their efforts on this case. We would like to also thank our partner agencies on extraditing Mr. Arreola-Murillo back to Utah to account for his crimes.”

Gill had previously explained that Arreola-Murillo will face life in prison, not the death penalty, due to diplomatic restrictions on defendants extradited from Mexico. In other words, the Mexican government only extradites individuals after being assured that person will not be put to death.

The murders

According to an autopsy and a declaration of probable cause reviewed by Law&Crime, Mejia was strangled to strangled to death on Feb. 9, 2006 by a ligature that was still around her neck when her husband — and, subsequently, the police — found her body. The autopsy ruled that the fetus had died by “maternal demise.”

Mejia’s husband reported to the police that the victim’s valuables, including her keys, car, some jewelry, and a religious pendant, were all missing — but the killer had apparently left some clues behind.

At the home, officers found “Cheetos spilled over the entry way, both inside and outside the front door.” A discarded bag and a Coke bottle were just inside the door. The victim’s husband told them that no one there drank Coke “and that Cheetos are not regularly kept in the apartment.”

Investigators said they obtained fingerprints and DNA from the “Cheetos bag and Coke bottle” that were later matched to Arreola-Murillo.

The court papers say a neighbor reported seeing “a Hispanic male leaning against the door frame to Ms. Mejia’s apartment” at about 11:30 a.m. the day she died. The neighbor then provided to police a harrowing description of what happened next.

“Ms. Mejia was standing just inside the door, speaking with the male,” court documents state. “Mr. Torres stated that the male grabbed Ms. Mejia by her throat and hit Ms. Mejia on the side of the head. Ms. Mejia fell to the floor inside of the apartment. The male entered the apartment and kicked the door shut.”

Exactly two years later, on Feb. 9, 2008, Arreola-Murillo killed Castillo in a similar fashion.

“Officers located the body of Damiana Castillo just inside the front door. Ms. Castillo had a ligature around her neck,” the police report stated. “A small table near the door was overturned, indicating a struggle occurred at the front door. The contents of Ms. Castillo’s purse, including her wallet, had been dumped out onto the couch and Ms. Castillo’s jewelry boxes had been disturbed.”

In this case, investigators also recovered a fingerprint print on the victim’s wallet and a DNA profile from the ligature around the victim’s neck.

“The DNA profile is consistent with the DNA profile obtained from the ligature around Ms. Mejia’s neck and the Coke bottle from Ms. Mejia’s apartment,” the police wrote.

Due to the strength of the DNA and fingerprint evidence in Mejia’s death, prosecutors on Feb. 8, 2010, filed a so-called “John Doe” information and warrant for the arrest of the suspect — assuming he would some day be found.

The database in 2016 provided confirmation that the prints from both crime scenes belonged to Arreola-Murillo.

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Aaron Keller contributed reporting to this story.

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Jerry Lambe is a journalist at Law&Crime. He is a graduate of Georgetown University and New York Law School and previously worked in financial securities compliance and Civil Rights employment law.