It happened around 3:45 p.m. at the Windsor at Tryon Village Apartments in the 8100 block of Underwood Arbor Place.
Officers on arrival found the bodies of Majda Massri, 55, and her estranged husband Abderrahman "Abdul" Rajab, 60, inside the apartment. Both had gunshot wounds.
Police confirmed this is a domestic violence case, and there is no ongoing threat to the public.
The investigation continued through the night into Saturday morning. A gun was found at the scene.
Both victims have been taken to the Office of Chief Medical Examiner. Autopsies have been scheduled to determine official cause of deaths, authorities said.
A man who lived at the complex told ABC11 that before the shooting, he heard what sounded like an argument in a language he did not understand, and then he heard two gunshots and then silence.
"Muffled shot, sounded like someone, like, slammed something on the ground. It woke me up. Words were exchanged, a man it sounded like, and then 20 seconds later, another one and nothing else," the resident said.
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One person who said they were a friend told ABC11 that the people found inside the apartment were a married couple, who had three grown children -- two daughters and a son. The friend said the couple was from Syria and were in their mid-to-late 50s.
The friend added that the wife had recently decided to separate from the husband after more than 20 years of marriage, and that he had been battling some bouts of depression.
Family members who arrived at the scene said they were too emotional to talk about the incident.
Cary Police said late Friday night that investigators are continuing their investigation and no more information would be released until Saturday.
Wake County Bureau of Forensic Services investigators are examining the apartment, and police are waiting for family members to arrive from out of town.
This remains an ongoing investigation.
Anyone with information is asked to call the Cary Police Department at (919) 469-4012. No further information is available for release at this time.
Featured video is from a previous report.
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