Jonathan Hurst, 51, faces two counts of first-degree murder.

A man was arrested this week in the double slaying of an 85-year-old woman and her son — and authorities say they found the suspect through DNA and genealogy databases.

Patricia Wilson, 85, and her son Robert Wilson, 64, were found dead in their home in Sycamore, Illinois, in August 2016, according to the DeKalb County Sheriff’s Office.

The Wilsons were killed from blunt force trauma in a “horrific and unprovoked act of violence,” DeKalb County Sheriff’s Office Chief Deputy Andy Sullivan said at a news conference on Tuesday.

The arrested suspect, 51-year-old Jonathan Hurst, had no known connection the Wilsons or the Sycamore area, Sullivan said.

Authorities believe Hurst acted alone to commit the “random act of violence,” Sullivan said.

When authorities began to investigate and search for a suspect, they discovered “a significant amount of physical evidence,” Sullivan said.

A DNA profile was obtained from the crime scene, which helped eliminate several persons of interest, Sullivan said.

Then Sullivan said investigators turned to Parabon NanoLabs, a company that’s cracked dozens of cold cases by using genetic genealogy.

Through genetic genealogy, an unknown killer’s DNA from a crime scene can be identified through his or her family members, who voluntarily submit their DNA to a genealogy database. This allows police to create a much larger family tree than using law enforcement databases like the Combined DNA Index System (CODIS).

To crack the Wilson case, investigators and Parabon analysts took the DNA from the crime scene and entered it to public genealogy databases to try to narrow down possible suspects. The analysts built a family tree based on that DNA, which led to Hurst, Sullivan said.

Cell phone records and other evidence confirmed Hurst was near the victims’ home on the day of the crime, Sullivan said.

A car was stolen from the victims’ home and later recovered in Chicago, near where Hurst lived, Sullivan said.

Hurst, who formerly lived in Chicago and now lives in Cincinnati, Ohio, was arrested at his home on Monday, Sullivan said. Hurst is awaiting extradition to Illinois to face two counts of first-degree murder, Sullivan said.

If convicted on both counts, Hurst faces a mandatory life sentence, DeKalb County State’s Attorney Rick Amato said.