Sonia Mejia and Damiana Castillo died 1 mile and two years apart, and police have long believed the same man murdered them.

DNA taken from crime scenes — Mejia died in Taylorsville on Feb. 9, 2006; Castillo in West Valley City on Feb. 9, 2008 — matched, but that DNA didn’t belong to anyone whose genetics were already in law enforcement databases.

Now, law enforcement has a name to go with the DNA.

“We know who it is,” Salt Lake County District Attorney Sim Gill said Thursday in a phone interview with The Salt Lake Tribune.

Gill did not disclose the suspect’s name, but he added, “This person is in another jurisdiction, and we want to be able to effectuate an arrest.”

Gill was more candid earlier with ABC 4, which reported the development Wednesday. The station paraphrased Gill as saying the suspect is serving jail time in another state, he doesn’t know he is charged in Utah, and there is concern he could be released accidentally from jail and flee.

“We know where this person is, and we are working to bring that person into our jurisdiction,” Gill told ABC 4 in a broadcast.

Sonia Mejia

Salt Lake County prosecutors filed two counts of aggravated murder in 2010 for the death of Mejia, who was six-months pregnant, and her unborn child. The defendant was listed only as John Doe. A technical description of his DNA stood in for normal identifiers such as birthday and address.

Court records suggest prosecutors have known Doe’s real name for some time. In April 2017, prosecutors, with no public announcement, filed under seal new documents in Doe’s case.

The filings themselves are not available, but a docket describes them as “Amended Information,” a reference to the document that describes the suspect and the charges, and an “Amended Warrant of Arrest.” Gill on Thursday cited a judge’s order to seal the filings as the reason he couldn’t disclose more.

Doe also was charged in 2010 with two counts of aggravated robbery, a count of aggravated burglary and a count of aggravated sex assault — all of which list Mejia as the victim. The charges were filed a day before the statute of limitations would have expired on the robbery, burglary and sex assault charges. It’s unclear whether the amended charges filed under seal include counts related to Castillo’s death.

When police make DNA matches in cold cases, they typically seek corroborating evidence, including taking a new genetic sample directly from the suspect. It’s also standard practice for detectives to seek documentation the suspect was in the vicinity of the victims when the crimes were committed — if only so defense attorneys can’t argue the DNA match is just a lab mistake.

The police departments in West Valley City and Taylorsville formed a task force in 2009, when the links between the Mejia and Castillo slayings were discovered. For years, when the anniversaries came around, the two forces had extra officers patrolling the two cities to prevent a third slaying.

Taylorsville joined the Unified Police Department in 2012. Representatives of the UPD and West Valley City police did not return messages seeking comment Thursday.

Mejia was 29 when she was killed at her apartment at 1167 W. Clubhouse Drive (3390 South) in Taylorsville. She was last seen alive in the morning when she took her 8-year-old son to school. A man police have described as Mejia’s common-law husband came home about 6 p.m. to find her dead in the apartment bedroom.

The 2010 charging documents revealed a witness observed a Latino holding a bottle of Coke and a bag of chips leaning against Mejia's door and talking with her. The witness told police the man hit Mejia on the side of the head, pushed her into the apartment and kicked the door shut, charges state.

Mejia's husband later found a bag of Cheetos and a Coke bottle inside the front doorway, according to the charges. He found Mejia partially nude on the bed with a dark blue bandana around her mouth and a wire around her neck; there was an orange substance consistent with the color of Cheetos on Mejia's right breast, charges state.

The husband told police that neither the bandana nor the ligature belonged to him or Mejia. The keys to Mejia's gray 1998 Ford Escort were missing. The car was found five days later in a motel parking lot about 12 blocks from her home.

Police believe the killer also stole three pieces of jewelry: a heart-shaped ruby ring, a diamond ring and a medallion of Our Lady of Guadalupe fastened to a gold necklace. In the days after the killing, police released to the public photos of what the jewelry looked like in the hopes of generating tips.

Fewer details have been released about Castillo’s death. She was 57 years old and lived at 4000 S. Redwood Road (1700 West) and was found by her son, who went to her home after she failed to show up at church on Feb. 10, 2008.