'Unspeakable tragedy': Death of pregnant teen and boyfriend now capital murder case

The mysterious deaths of a pregnant teen who was about to give birth and her boyfriend are now being investigated as a capital murder case, San Antonio police said.

Calling the case an "unspeakable tragedy," police said they were looking for two persons of interest after 18-year-old Savanah Soto and her boyfriend were found dead days after the Texas mom-to-be was scheduled to be induced.

Police initially said an 18-year-old full-term pregnant woman and a 22-year-old man believed to be Soto and her boyfriend, Matthew Guerra, were discovered dead in a Kia Optima in San Antonio on Tuesday. An unborn child was also found deceased, police said. The vehicle had been at that location for likely several days, police said.

In the days following the discovery, the medical examiner has positively identified the victims as Soto and Guerra, police said.

Both victims had a gunshot wound, police said.

Guerra died from a gunshot wound to the head, though the medical examiner has not yet determined the manner of death, San Antonio Police Chief William McManus said during a press briefing Thursday. Right now police do not believe this to be a murder-suicide though the chief noted "that possibility exists."

The case is currently being investigated as a capital murder for both victims, he said.

"It was a heinous act, it was unspeakable, the tragedy of it," McManus said.

Police released footage on Thursday of two persons of interest being sought in connection with the case. One was captured driving the victims' Kia Optima, and the other was seen driving a dark-colored pickup truck, police said.

The person of interest in the pickup truck is seen talking to the driver of the victims' car. McManus said they do not believe either victim appears in the video.

McManus had called the case "very, very perplexing" following the discovery of the bodies.

"It was undetermined at that time whether we were going to be looking at it as a murder-suicide, or as a capital-murder investigation," he said Thursday. "I think we've gotten past that point right now, unless we get evidence that would lead us to believe otherwise."

Soto, 18, was last seen on Dec. 22 in Leon Valley, according to the Texas Department of Public Safety. The agency issued a CLEAR Alert -- used to help law enforcement locate someone in imminent danger or whose disappearance is involuntary -- for Soto on Monday.

The pregnant teen had passed her delivery date, which "caused significant concern among her family members after missing an essential medical appointment," the Leon Valley Police Department said in a press release earlier on Tuesday.

Soto's mother, Gloria Cordova, told San Antonio ABC affiliate KSAT that her daughter was scheduled to be induced at a hospital this past Saturday.

"When I called her all morning she wasn't answering, was going straight to voicemail," Cordova told the station. "We went to the hospital anyways. She was a no-show, and that's when I called the cops."

Cordova said her daughter's home was clean and had been prepped for the baby's arrival.

"This is not like her," Cordova told KSAT. "She was so excited to have this baby. The house was already baby-ready."

Detectives are combing through social media and cellphone records, as well as days of surveillance video from several different locations where the victims were known to be, the chief said.

"Detectives are hopeful that surveillance video will lead to the events leading up to their death," McManus said.