"I can't believe I'm even saying Rest in Peace Sutton," Simmons wrote in an emotional social media post
Angela Simmons
Credit: Source: Angela Simmons/Instagram

Angela Simmons is mourning the loss of her ex-fiancé and father of her only son, Sutton Tennyson, who was shot and killed on Saturday.

The Atlanta Police Department tells PEOPLE that officers responded to a call of shots fired shortly before 5 p.m. on Saturday.

Although the police declined to formally identify Tennyson, they shared that “upon arrival, officers discovered a 37-year-old black male lying deceased, with multiple gunshot wounds, inside an open garage.”

According to their preliminary investigation, shots were fired after a conversation with another male escalated. After firing multiple shots, the suspect then “sped from the scene in a car.”

The case is currently under investigation by the APD’s homicide unit.

A spokesperson from the Fulton County Medical Examiner’s Office confirmed to PEOPLE that Tennyson had been identified as the victim.

On Sunday morning, the Growing Up Hip Hop star — who is the daughter of Run D.M.C.’s Rev. Run — posted a series of touching tributes to Tennyson, writing that she was “hurting” and “numb.”

“Thank you for leaving behind my greatest gift,” wrote Simmons, 31, on Instagram alongside a series of family snaps.

“I’m hurting. I’m numb. Thank you for the out pouring [sic] of love everyone,” she continued, adding that she couldn’t “believe I’m even saying Rest in Peace Sutton.”

Concluding the message, she made a pledge to always watch over their son, Sutton Joseph, 2.

“I promise to hold SJ down in every way I promise,” she wrote, adding a heart emoji.

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She also shared numerous photos of Tennyson and their son together on her Instagram Story.

In one throwback shot, Tennyson stood behind her with his arms around her, while they cradled their newborn baby together.

Angela Simmons, Sutton Tennyson and Sutton Joseph
| Credit: Angela Simmons/Instagram
Sutton Tennyson and Sutton Joseph
| Credit: Angela Simmons/Instagram

“We made an angel,” she wrote alongside the shot.

Alongside an image of Tennyson taking a nap on the couch with their child, she touchingly wrote, “Rest easy Sutton.”

Simmons star confirmed her split from Tennyson in December 2017.