The parents of Nygil Cullins, 22, say the Atlanta Police Department failed to properly manage a 911 call about their son having a mental health crisis, but the department defended the officer who fatally shot him after he fired a gun at a security guard.

Cullins’ mother, Maya Cullins, told local Atlanta station WAGA that her son was having mental health issues on May 18, so she called 911 to have him taken to a mental health facility.

"My biggest fear when I got on the phone with them - I said ‘he’s an African-American male, please make sure whoever shows up is trained and knowledgeable so when they deal with my son, I don't have to worry about him being killed," she explained.

Cullins left the house before medics and police showed up and went to Fogo de Chão Brazilian Steakhouse in a suburb of the city.

According to Atlanta police officials, an officer responded about 7 p.m. that night to a call about an armed man at the restaurant, WAGA reported. Witnesses later said he was being “rowdy” and drinking alcohol from a bottle. The officer found Cullins sitting at the bar. He started a scuffle with the cop and a security guard after refusing their order to leave the restaurant.

The police say the officer fired a Taser at Cullins, but it was ineffective. After the security guard tackled him, Cullins fired his gun, striking the security guard who survived the shooting. The officer returned fire, fatally shooting Cullins.

Cullins’ father, Quinten Cullins, told local station WSB that the system failed his son, adding, “He had a heart of gold.”

RELATED: Cops Shoot And Kill Mentally Ill Black Man In Walmart And People Want Answers

The Atlanta Police Department sees it differently. “Our officer did a great job to isolate the subject to the front of the business where no patrons were in harm’s way,” WSB quoted a police spokesperson.

However, the Georgia Bureau of Investigation will investigate the police-involved shooting and submit its findings to the Fulton County District Attorney’s Office, WAGA reports.