Soon after gas station clerk Donna Pena was shot dead during a March 2019 robbery, sheriff’s deputies combed the neighborhood looking for evidence.

About two blocks northwest of the crime scene, they found a blue sweatshirt, inscribed with “NAVY,” that surveillance video showed belonged to one of the suspects. Investigators took a DNA sample from the sweatshirt, but it didn’t return any matches.

Until 11 months later.

On Monday, investigators received word that the sample had a match from the Texas Department of Public Safety, a break in the nearly year-long case that led to the arrest Friday night of 20-year-old Marcus Kenneth Cox-Davis.

Sheriff Ed Gonzalez said Friday night that a new state law, which requires a person to give a DNA sample if the are arrested for certain felony offenses, was responsible for the link. Cox-Davis had provided the sample after he was charged with another aggravated robbery in November.

The “Krystal Jean Baker Act” passed the Legislature last year, and Gov. Greg Abbott signed it into law in June. Baker, 13, was a teen girl murdered in Chambers County 1996. Her killer was caught using DNA evidence in 2010.

Prosecutors described the Pena murder investigation early Saturday at Cox-Davis’ initial probable cause hearing in Harris County District Court, where a magistrate denied him bail.

Cox-Davis did not appear at the hearing.

Investigators say he and another man ran into the Shell gas station near FM 1960 and Perry Street on March 8, 2019, wearing hoodies with bandannas covering their faces.

Prosecutors said Saturday that Cox-Davis, wearing the Navy sweatshirt, held a handgun against the back of Pena’s head as she attempted to open the cash register. His accomplice took Pena’s purse and cell phone.

Before Pena could open the drawer, Cox-Davis allegedly fired the handgun, killing her. Pena had two children, ages 4 and 15.

An appointed defense attorney told a judge during the hearing that the crime was certainly horrific, but it’s too soon to tell whether the DNA sample on the sweatshirt necessarily means that it was Cox-Davis wearing it that night at the scene of the murder.

Investigators believe the two men are responsible for a slew of other aggravated robberies as well.

When the DNA match came in, sheriff’s deputies checked Cox-Davis’ criminal history and found the November 2019 case.

When police arrested him and his co-defendant for that crime, they were found inside a car in a Valero parking with a gun, “wearing facial coverings by all appearances preparing to commit another aggravated robbery.”

His co-defendant in that November case, Thomas Alford, was also charged with an aggravated robbery of a Subway in February 2019, a month before Pena’s murder.

Surveillance video in that case showed Alford robbing the store with another man authorities believe to be Cox-Davis. The video shows him wearing the same Navy sweatshirt.