Surveillance footage has emerged showing Alyssa Ann Rivera, a Texas woman found dead inside an abandoned home, walking alongside a male ‘person of interest’ shortly before her death.X

Authorities believe there is a serial killer at work in central Texas after DNA linked a June murder in Austin to a murder six years ago in neighboring Bastrop County.

On June 21, the Austin Police Department responded to an abandoned home on Metcalfe Road and discovered a deceased woman later identified as 34-year-old Alyssa Ann Rivera. Investigators say she was sexually assaulted and strangled. Police released surveillance footage of Rivera walking with an unknown man shortly before her death.

Police believed the murder was an isolated case until earlier this month, when DNA from the crime scene was matched to DNA from the scene of the 2018 murder of 28-year-old Alba Jenisse Aviles.

That killing was being investigated by the Bastrop County Sheriff's Office.

Aviles had been in Austin the night before she was found dead, and her body was found only about three miles from the location where Rivera was found, police said. Aviles had also been sexually assaulted and strangled, and police say both crime scenes appeared to have the same characteristics.

Surveillance footage has emerged, according to Fox News, showing Alyssa Ann Rivera, a Texas woman found dead inside an abandoned home, walking alongside a male 'person of interest' shortly before her death.

Speaking at a press conference on Thursday, Austin Police Sgt. Nathan Sexton said the DNA of the unknown suspect did not match any records in the national Combined DNA Index System. He said it is "relatively rare" for a person who commits "really violent murders" to not have an arrest record for previous crimes.

The Bastrop County Sheriff's Office said it has been working with the Texas Rangers to "explore genealogy" to potentially identify the DNA of the suspect.

--with reporting by TMX