AUBURN – Jurors returned a guilty verdict Friday in the weeklong trial of a Lisbon man charged with assaulting his 21-month-old son the day before the toddler died.

The verdict against Jeremy Allen followed three hours of deliberations over two days in Androscoggin County Superior Court.

Allen, 30, was released on bail while he awaits sentencing in November. His conviction of assaulting a child under age 6 carries a maximum sentence of five years in prison.

Allen told the jury that he struck his son Nathaniel on his bare buttocks three times with a wooden spoon on the night of Feb. 13, 2003, after the boy refused to obey his mother’s instructions to pick up his toys.

Bruises on Nathaniel’s bottom were discovered after he was transported unconscious to Maine Medical Center the following evening with head injuries. Allen, a Navy journalist, was away at the time on a business trip.

Allen’s wife, Sarah, was charged with manslaughter for allegedly causing the child’s death by shaking him. Her first trial ended when jurors were unable to agree on a verdict; she is scheduled to be tried again next month.

Deliberations began Thursday afternoon after Assistant Attorney General Lisa Marchese and defense counsel George Hess called medical experts as witnesses to discuss the extent of Nathaniel’s bruises.

Hess’s expert, Dr. Arthur Weiss, a retired specialist in blood diseases, said Nathaniel developed an abnormality as a result of the trauma suffered the following day to his head. The condition, he said, prevents blood clotting and would have resulted in bruises appearing much worse than they would otherwise.

Dr. Eric Gunnoe, a staff pediatrician with Maine Medical Center, countered for the state that the bruises were consistent with child abuse, a specialty he has studied both in Maine and elsewhere.

During cross-examination, Marchese challenged Jeremy Allen’s assertion that the spanking he gave his son was consistent with what he had learned from parenting books. The prosecutor suggested that he could have found other means to punish Nathaniel.

Allen responded by telling jurors, “I spanked him because I loved him.”

“Children need healthy boundaries” that help to define relationships, he said, and spankings were “part of my toolbox” of parenting skills.