NEW YORK (CBSNewYork/AP) – A former Rikers Island guard convicted of kicking an inmate to death has been sentenced to spend 30 years behind bars.

Brian Coll, of Smithtown, was sentenced Wednesday by federal Judge Loretta Preska in Manhattan. He was convicted in December of violating the civil rights of 52-year-old Ronald Spear.

Spear died in 2012 after he was repeatedly kicked in the head while restrained on the floor outside a jail doctor’s office. Prosecutors said he became agitated because he could not immediately see a doctor.

As WCBS 880’s Alex Silverman reported, a short, stocky Coll stood in beige prison scrubs Wednesday and told the judge in a gravely, New York accent that he’s truly sorry he lost control of himself.

“I am no killer,” he said.

Preska wasn’t having it.

“He kicked a man to death in the head,” she said.

Spear, who was being held on a burglary charge, was a sick man who needed dialysis and a cane, Preska added. She said Coll committed the crime over the cries of his fellow correction officers and kept a trophy – a newspaper photo of the victim – like he was proud of what he’d done.

The judge said the sentence of 30 years — more than the government requested — was intended to be a deterrent, considering what she called a culture of violence on Rikers Island.

“Now they’ll know not to do it to the next folks, because the next family won’t have to go through this,” the victim’s cousin, Donna Spear, told Silverman, adding that Coll wouldn’t have done this to a person on the street.

She said it happened because he had the power.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)