Two people were killed and two others injured in a shooting at Boston rapper Cousin Stizz's concert in Atlanta over the weekend.

Atlanta Police spokesman Sgt. John Chafee told news outlets that officers responding to a report at the Masquerade at Underground Atlanta found four people shot Sunday night. One person was pronounced dead at the scene and another was pronounced dead at a hospital.

Police said the two remaining victims were bystanders who were shot in their legs and are expected to recover.

They believe a lone man targeted two people before fleeing. Police are still seeking the suspect and asking for witnesses to come forward.

According to local NBC affiliate WXIA-TV, the shooting occurred after the two victims who were fatally shot climbed up onto the stage during an intermission. An argument ensued, and another person pulled a gun and shot the two victims before firing toward the ground, resulting in the injuries to the two other people.

Cousin Stizz, who is slated to play the House of Blues in Boston on Nov. 24, was one of four acts scheduled to perform at Sunday's concert.

"Completely heartbroken," the rapper said on Twitter after the shooting. "Before I hit the stage in Atlanta tonight, there was a shooting in the crowd, two people died and two others were injured. I've always called my shows family reunions because they're never anything but fun, safe, good vibes and positivity. I'm in shock and at a loss of words for the senseless violence. My thoughts and prayers go out to the victims and their families."

He said his scheduled concert on Monday night in Washington, D.C. has been canceled due to Sunday night's events.

Cousin Stizz, 25, is based in Los Angeles, but grew up in Boston's Dorchester neighborhood. He signed a record deal with RCA in 2016, and was among the dozens of artists who played at Boston Calling last May.