BATON ROUGE - A 28-year-old linked to a shooting that left a pregnant mother and her unborn child dead was arrested more than a month after the killings.

Family tells WBRZ that Kimberlyn Martin was with her boyfriend, Dorian Burns, outside of an apartment at Elevate on Highland when her boyfriend's brother, Alex Burns, opened fire.

"From what I was told, he was aiming for Dorian, Dorian was running upstairs because Kimberlyn was staying upstairs on the second floor. He was running upstairs, Kimberlyn came out of her apartment, and he shot her as well," Denisha Martin, Kimberlyn Martin's cousin, said. "I don't know why his own brother would try to kill him. And then kill his baby mama and unborn child in the process?"

The Baton Rouge Police Department announced Burns, 28, was arrested for first-degree murder and attempted first-degree murder. 

Both victims were taken to a hospital, where Martin and her baby died.

Martin's family believes Dorian Burns was not forthcoming with information regarding the night of her death.

"He kept saying, 'Oh, I don't know, I'm sorry, I'm sorry, I don't know.' Like how you don't know? You don't know who was shooting at you? The math is not mathing. You've got to make it make sense," Denisha Martin said. "That was going to be Dorian's first kid. You don't want justice for your unborn child?"

Police said Burns was arrested Sept. 3 with assistance from the U.S. Marshal’s Fugitive Task Force.

Martin's family say they want to know the motive behind her death.

"Why? She had her whole life ahead of her," Mercedes Martin, her cousin, said.