Portland, MAINE (NEWS CENTER) Justices of the Maine Supreme court heard arguments this morning in a case involving the death of a baby in Bangor. The infant's father, Dustin Brown, was convicted of criminally negligent manslaughter in the case. He was sentenced to serve four and a half years in prison for the death of 3-month old Xander Brown. Brown told investigators he was feeding the baby when the infant went limp. The state claimed the baby died after being violently shaken. Brown's attorney argued this morning the state failed to prove exactly how the baby died and exactly what actions Brown took that caused the death.