A former police officer in Rhode Island has been sentenced to one year and a day in prison for beating up a teenage boy in his custody.

The sentence imposed Friday on John Douglas was shorter than the 18-month prison term sought by federal prosecutors but harsher than the home confinement requested by his lawyer.

Douglas pleaded guilty in June to a federal civil rights charge for beating up the boy inside a stairwell at the Woonsocket Police Department in September 2009. Douglas, who has since resigned, apologized at his sentencing hearing.

U.S. District Judge Mary Lisi said Douglas's actions were unacceptable and that he needed to be punished to deter other police officers.

Douglas's lawyer, Thomas Briody, argued that Douglas was an excellent police officer who lost his composure and was dealing with mental health issues.