A mother and son found murdered in their Lewisville home were killed “execution-style,” according to police.

Lilia Fernandez Ortiz, 66, and her son, Alejandro Arrellano-Fernandez, 43, were found dead on August 14. They had both been shot in the head. They were found inside their home on Ramblewood Drive after a relative was unable to contact them and arrived at the residence for a welfare check, as previously reported by The Dallas Express.

Jawara Oji Black, 51, and Samuel Melkamu, 37, have been arrested in connection with the homicide. Black was arrested Monday in Houston, per Fox 4 KDFW. They are both currently being held in Denton County Jail.

Black was charged with two counts of capital murder. His bail was set at $100,000. Melkamu was charged with two counts of capital murder, with his bail set at $1.5 million, according to jail records.

Footage captured by a neighbor’s security camera led to the arrests. According to the arrest warrant affidavit, the footage shows two men approaching Arrellano-Fernandez outside the home and shoving him to the ground. Melkamu allegedly pulled out a gun, and the three individuals fought off-camera. Shortly after that, a brass bullet casing can be seen rolling across the ground into the frame, and the man purported to be Black can allegedly be seen dragging Arrellano-Fernandez into the driveway of the home, Fox 4 reported.

Four days later, Arrellano-Fernandez’s body was found in the garage, and Ortiz’s body was found in the kitchen. According to the affidavit, both individuals were shot “execution-style,” per Fox 4.

Neighbors indicated that one of the suspects was a homeless individual in the neighborhood called “Sam,” who was known for doing small jobs, per Fox 4.

The arrest warrant affidavit did not indicate a motive for the murders.

In Dallas, there have been 160 criminal homicides this year as of August 24, an increase of roughly 5% over last year, according to the City of Dallas Open Data crime overview dashboard.

The Dallas Police Department has been severely understaffed for some time now. There are currently only around 3,100 police officers in the department, roughly 900 short of the 4,000 recommended by a City report.

Dallas Police Chief Eddie García noted that the shortage is not limited to Dallas, according to The Dallas Morning News.

“We are in a national hiring crisis for police officers. … There’s just no question about it,” García said.

While Fort Worth has struggled to maintain its own police force, its downtown area is bolstered by a dedicated neighborhood police unit and private security guards. It has been seeing considerably less crime than Downtown Dallas.