A Missouri man accused of killing a 36-day-old baby was not only the boyfriend of the child's mother, but was also her uncle.

That was part of what came to light in the first day of Steven Zorn's first-degree murder trial, which continued Wednesday in Buchanan County District Court. Zorn is charged in the beating death of Cora Jean Lockhart on Jan. 7, 2008.

Prosecuting Attorney Dwight Scroggins told jurors that Zorn started dating the baby's mother, Suzan Lockhart, when she was pregnant by Zorn's half-brother, David Petty.

Cora Jean was born Dec. 2, and by then Zorn lived with Lockhart and her two other children.

Just over a month later, Scroggins said, the baby was beaten to death.

Defense attorneys don't dispute the baby's cause of death, but believe evidence will show that Zorn did not knowingly kill the child with deliberation.