Brielle Biermann Says Her Friend's Hit-and-Run Death Is the 'Hardest Thing' She’s Been Through

Brielle Biermann posted on Instagram for the first time since announcing the death of her friend Ethan McCallister.

McCallister died at age 28 in a hit-and-run accident.

Brielle, 24, shared photos of her with her mother Kim Zolciak-Biermann, her stepfather Kroy Biermann, her sister Ariana Biermann and close friends. All of them were wearing black in honor of McCallister.

"i am so thankful for my family and friends🖤," Brielle began in the caption.

Brielle Biermann/instagram

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The Don't Be Tardy star then shared that's she's read all of "the kind messages" she's received from fans.

"While losing Ethan has been the hardest thing I've ever gone thru, i am finding comfort knowing how much love and support i have🖤," Brielle concluded.

Brielle Biermann/instagram

McCallister was struck by a vehicle at Piedmont Avenue and Lindbergh Drive in Atlanta, as he was out walking at about 3 a.m. local time, according to WSB-TV, which reported that police are searching for the suspect, who left the scene, driving a dark-colored SUV.

A spokesperson for the Fulton County Police Department did not immediately respond to PEOPLE's request for comment.

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Following McCallister's death, both Brielle and Kim, 42, took to Instagram expressing their grief.

"Ethan.... i can't believe I'm even writing this. I'm sick sick sick to my stomach," Brielle wrote at the time.

The 24-year-old continued, "You are my happiness my joy my light in this very dark world.. the life of the party and the sweetest soul I've been blessed to know. You are my best friend. My heart. My everything. There will never be another you. Ever ever ever. "

Brielle also shared how well her friend was at making her smile. "There was never a moment i wasn't laughing with you!!" she said.

Kim similarly expressed that her daughter's friend was "the life of the party" and had a "huge beautiful smile."

"One of the most genuine kind hearted people I have ever known ❤️ Always willing to help anyone anywhere," the former Real Housewives of Atlanta star wrote. "We love you Ethan and I will make sure justice is served."

Prince Williams/Wireimage

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Kim and Brielle asked their combined 4.4 million Instagram followers for help in identifying the driver, also sharing a link to the family's GoFundMe to cover costs for his funeral.

Anyone with information regarding the driver – who used a gray Jeep Grand Cherokee – is being asked to contact Atlanta police or submit a tip to Crime Stoppers Atlanta at 404-577-8477 or on its website.