A Las Vegas man has been charged with double murder after he allegedly shot and killed his ex-wife and her new husband at their shared workplace on Tuesday.

Police say Alejandro Estrada, 43, entered the Smith's grocery store where the couple worked and immediately opened fire. He was eventually tackled by patrons in the store who held him down until police arrived.

The victims, Amanda Rosas and Victor Frias Rosas, were pronounced dead at the scene.

Amanda married Rosas last year, but she and Estrada were still in the midst of a tense custody battle over their 12-year-old son and 9-year-old daughter. Estrada owed her over $2,800 in child support payments, according to the New York Post.

Police say Estrada had multiple weapons at the time of the attack. He is now facing 12 charges, including two counts of murder.

"He was completely calm. No expression. No nothing," shopper Paula Milton Police Department (LVMPD) told Fox News Digital.

Nearby surveillance video captured a brief, suspicious encounter in the middle of the night, showing a suspect approaching the victim’s area and leaving about a minute later, the Review-Journal reported, citing police records.

"The precise location of the crime scene was obstructed from surveillance cameras, but video surveillance with audio … captured the suspect approaching Marceline’s location and, seconds later, a scream is heard followed by approximately 61 loud thuds," the Review-Journal report said.

Geiggar had recently been expelled from a nearby high school for allegedly trying to start a fire on campus. Police said he had "numerous incidents where his anger had resulted in his punching walls and trash cans" and had been participating in anger management classes, according to the outlet.

Fox News' Bonny Chu contributed to this report.