Kim Zolciak-Biermann and Daughter Brielle Mourn the Death of Their Family Friend in Heartbreaking Post

Brielle Biermann and Kim Zolciak-Biermann
Prince Williams/Wireimage

The 'RHOA' star shared that her daughter's friend was killed in a hit and run on Friday night.

The Zolciak-Biermann family is mourning the death of their close friend, Ethan McCallister.

Kim Zolciak-Biermann and daughter Brielle Biermann took to Instagram on Saturday to express their sadness over Ethan's death. The 42-year-old  Don't Be Tardy star revealed that the 28-year-old was killed in a hit and run around 3 a.m. on Saturday while out in Atlanta, Georgia.

Brielle posted a photo of her "best friend," expressing how "sick to my stomach" she was over the accident.

"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," the 24-year-old wrote. "There will never be another you. Ever ever ever. You came into this world with 1 mission... make people smile. You were damn good at it too. There was never a moment i wasn’t laughing with you!!"

She added that they hadn't spent one weekend apart this whole year, expressing, "How am i supposed to go anywhere without you?" she concluded by writing, "God i love you ethan. I really really do. I can’t wait to see you again."

Kim also posted a selfie of Ethan and Brielle, writing, "We will miss your huge beautiful smile, constant jokes, cowboy boots and infamous shirts. You were always the life of the party!! One of the most genuine kind hearted people I have ever known ❤️ Always willing to help anyone anywhere."

She added that she will "make sure justice is served," before sharing details on the accident and encouraging people to call the Atlanta police if they had any information. The reality star also posted his family's GoFundMe page for his memorial.

Atlanta police told 11Alive that Ethan was taken to the hospital, where he died after being hit by a car. Official told the news site that the driver did not stop and kept going. Police are currently looking for the driver.