Indiana has agreed to pay a convicted killer $100,000 for each of the four years he spent in solitary confinement, according to a Sunday report.

Jay Vermillion is serving a decadeslong sentence for murder and other offenses, The Indianapolis Star reported, citing an October settlement between him and the state.

State law says the maximum allowable solitary confinement term is 30 days. Officials then have to conduct a review.

Starting in 2009, Vermillion was put in solitary at Westville Correctional Facility. Attorney Maggie Filler of the Chicago-based MacArthur Justice Center said Vermillion was given more time without an explanation.

“Most people who enter prison are one day going to get out,” Fill said. “And they’re going to be living in free society. So it’s incumbent upon us to make sure that the prison experience is more rehabilitative than it is just purely destructive.”

Vermillion described his conditions in solitary as a cold “concrete tomb.” He had no direct contact with others.

FEDERAL PRISONER WHO SPENT 35 YEARS IN SOLITARY CONFINEMENT DIES

Indiana Department of Correction spokesman Dave Bursten said the agency settled the case to avoid the “uncertainties” and expenses of litigation. The department denies wrongdoing.

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The 59-year-old Vermillion was convicted of murder in 1997. He’s now detained at Pendleton Correctional Facility.

The Associated Press contributed to this report.