GARLAND, Texas (WJW) – A teenager who was the focus of an AMBER Alert issued overnight Thursday is now facing a murder charge alongside a man believed to be her abductor.

Garland police have named 17-year-old Natalie Navarro and 21-year-old Yordy “Jordy” Martinez as suspects in connection with the shooting death of 21-year-old Arturo Pena on Aug. 29.

A passerby alerted authorities after noticing a man who appeared to be unconscious. Upon arrival, police determined that the victim, later identified as Pena, had succumbed to a gunshot wound. Pena had been reported missing by Dallas police on Aug. 27.

During the investigation into Pena’s murder, Garland police identified Navarro as a person of interest and subsequently issued an AMBER Alert on Thursday evening. The alert stated Navarro was last seen at about 2:15 p.m., and that her life was believed to be in grave danger. However, the AMBER Alert was discontinued at about 3:30 a.m. when law enforcement in Webb County, in southern Texas, located Navarro. She was found safe and taken into custody.

Garland police announced on Friday morning that both Navarro and Martinez were wanted for murder, and warrants were being obtained for their arrests. The specifics of how they became suspects in Pena’s death have not yet been disclosed.

Lt. Richard Maldonado of the Garland Police Department expressed the department’s determination to uncover the motive behind the tragic incident.

“The reason why this happened, we’ve yet to totally determine that. We hope to get more when we talk to Natalie to see exactly what was going on — if these persons knew each other, if they had a relationship, if there was a falling out,” he told NBC DFW.

According to the booking report, Navarro is being held on a $1 million bond on a charge of “capital murder by terror threat/other.”

Under Texas penal code, that means the offender caused the death of another during another crime — including kidnapping, robbery, burglary, aggravated sexual assault, arson, obstruction or retaliation or terroristic threat — or attempted crime.

Though Navarro is now in custody, Martinez remains at large and is considered armed and dangerous.

The investigation into Arturo Pena’s murder is ongoing, and authorities urge anyone with information on Martinez’ whereabouts or details related to the case to contact Garland police or submit tips anonymously to Garland Crime Stoppers. A reward of up to $5,000 is being offered for information leading to an arrest.