The U.S. Supreme Court will not intervene in convicted killer Billy Ray Irick's execution, set to take place Thursday at 8 p.m.

U.S. Supreme Court Justice Elena Kagan denied a request to delay Irick's execution. However, U.S. Supreme Court Justice Sonya Sotomayor disagreed with her colleague's decision.

"In refusing to grant Irick a stay, the Court today turns a blind eye to a proven likelihood that the state of Tennessee is on the verge of inflicting several minutes of torturous pain on an inmate in its custody, while shrouding his suffering behind a veneer of paralysis," Sotomayor wrote in her dissent.

REMEMBERING WHY: 1985 rape and murder of 7-year-old Paula Dyer

MORE: Timeline of Irick's 33-year case

RELATED: Death row inmate Billy Ray Irick asks U.S. Supreme Court to delay execution

The high court's decision not to stop the lethal injection likely means Irick is truly out of ways to prevent his death by the state.

Irick, 59, was convicted in 1986 of raping and murdering Paula Dyer, a 7-year-old girl in Knox County. Advocates have long noted he has a history of severe mental illness, including delusions and paranoia at the time of his crimes.

In filings before the Supreme Court, Irick's attorneys said the court must decide if those who suffer from severe mental illness should be spared from execution.

The court already determined juveniles and people with developmental disabilities may not be executed. But the justices declined to weigh in, at least for the time being, on the question of culpability for severally mental ill death row offenders.

MORE: What happens if lethal injection drugs don't work?

RELATED: Last East Tenn. man to be executed was convicted of rape in1957

A Davidson County court, the Tennessee Supreme Court and a federal court in Nashville all rejected different legal pleas aimed at delaying or preventing Irick's execution.

If executed, Irick will be the first Tennessee inmate put to death since 2009.

This is a developing story. Follow Tennessean.com for more information as it becomes available.

Reach Dave Boucher at 615-259-8892, dboucher@tennessean.com and on Twitter @Dave_Boucher1.