Unified Police responded to their apartment on West Clubhouse Drive at approximately 6 p.m. and noticed "Cheetos spilled over the entryway, both inside and outside the front door." As officers went in, they found a Cheetos bag and bottle of Coke.
Mejia’s husband informed Unified Police that "no one residing in the apartment drank Coke and that Cheetos are not regularly kept in the apartment." He also said her keys, car, diamond ring, religious pendant, and heart-shaped ring were all missing.
A neighbor told police he saw a man talking to Mejia that day at around 11:30 a.m., and at one point, the man "grabbed Ms. Mejia by her throat and hit Ms. Mejia on the side of the head."
The medical examiner determined Mejia died from ligature strangulation and that her child, who was about 24 to 25 weeks along, did not survive due to "maternal demise." The medical examiner said they both died by homicide.
Investigators obtained fingerprints from the Cheetos bag and Coke bottle and put them into the Automated Fingerprint Identification System. DNA from the ligature was also added to the Combined DNA Index System.
Almost exactly two years later, on Feb. 10, 2008, West Valley City Police Department officers went to a residence at 4000 S. Redwood Road and found Castillo deceased with a ligature around her neck. The probable cause statement says police saw a small table overturned near the door, "indicating a struggle occurred at the front door."
Castillo’s purse had been emptied and her "jewelry boxes had been disturbed."
The autopsy showed Castillo died from asphyxia due to strangulation by ligature.
Detectives discovered a fingerprint on Castillo’s wallet and entered it into the Automated Fingerprint Identification System, which resulted in a positive match to the prints found on the ligature in Mejia’s apartment.
In 2016, Arreola-Murillo was identified as a match to both sets of fingerprints. The Salt Lake County District Attorney’s Office filed charges against Arreola-Murillo in 2017. He was reportedly serving time in prison in Mexico for aggravated robbery.