Apparently it would have been their second child together. He had a kid with the other young woman he killed, who was pregnant with their second child.

According to this article.

ETA: To clarify, this dude managed to create four pregnancies between two women, both of whom he killed. There's an infant and two toddler offspring out there that he created with the women he killed (the unborn fourth died when he killed that woman.) Children seem to have been present for both murders, with one toddler being left alone with his dying mother.

Apparently it would have been their second child together. He had a kid with the other young woman he killed, who was pregnant with their second child.

According to this article.