A Texas teenager, missing since Christmas Eve, was last spotted leaving her home that morning, and authorities have expressed concerns that she may be in “imminent danger,” law enforcement officials reported on Sunday.

Surveillance footage captured a person, believed to be 19-year-old Camila Mendoza Olmos, around 7:00 a.m. on Wednesday. The video shows her searching through her car for an unidentified item, according to the Bexar County Sheriff’s Office.

Investigators suspect that Mendoza Olmos left the premises on foot, as her vehicle was still parked at the location. It appears that the only items she took with her were her car keys and possibly her driver’s license.

The last confirmed sighting of her was in the 11000 block of Caspian Spring, located in northwest Bexar County, as stated by the sheriff’s office.

Bexar County Sheriff Javier Salazar informed ABC News on Sunday that both deputies and volunteers are working tirelessly, conducting a continuous search for Mendoza Olmos.

Multiple agencies have joined the search, including the FBI, which is providing technical assistance, and the Department of Homeland Security, which is monitoring border crossings and international travel, Salazar said.

“We definitely don’t want to miss anything,” Salazar said. “The ground search is somewhat limited to a couple of square miles. We’re also not ruling out that this case may take us outside the borders of the continental United States.”

Salazar said investigators have not ruled anything out in the teenager’s disappearance, including kidnapping, human trafficking and the potential she left on her own accord.

Salazar said Mendoza Olmos recently went through a romantic breakup, but authorities said the breakup was mutual and don’t suspect anything “nefarious” was involved, saying everyone close to her is cooperating.

Olmos was last seen wearing a baby-blue and black hoodie, baby-blue pajama bottoms and white shoes.

“Camila’s mother stated that Camila normally goes for a morning walk; however, she became concerned when Camila did not return within a reasonable period of time,” according to the sheriff’s office.

Salazar confirmed that Mendoza Olmos was not detained by U.S. Immigration and Customs Enforcement (ICE), despite her being a U.S. citizen.

“That was a personal concern. So, I had it checked to make sure that there were no stops, no detentions, and that she’s not somewhere in a federal detention facility. That is something we needed to check,” Salazar said.

Salazar noted that it was unusual for Mendoza Olmos to leave her phone at home, saying she leads an active lifestyle and it’s “highly unusual” that she hasn’t returned.

“That’s why we’re working basically around the clock on this case,” Salazar said.

While Salazar would not disclose some details of Mendoza Olmos’s disappearance, he said there is enough information to suggest she is in “imminent danger.”

Salazar requested help from the community in the search, asking neighbors of Mendoza Olmos to check their surveillance cameras for any footage of the teenager.

Anyone with information on her whereabouts is asked to call the Bexar County Sheriff’s Office at (210)335-6000 or the BCSO Missing Persons Unit via missingpersons@bexar.org.