BOISE, Idaho — The hour of Thomas Eugene Creech’s death has been set, and it is rapidly approaching.

The 73-year-old serial killer, one of the nation’s longest-serving death row inmates, spent time with his wife Tuesday evening and ate a last meal including fried chicken, mashed potatoes, gravy and ice cream.

On Wednesday morning Idaho prison officials will ask if he would like a mild sedative to help calm him before his execution at the Idaho Maximum Security Institution south of Boise. Then, at 10 a.m. local time, they will bring him into the execution chamber and strap him to a padded medical table.

Defense attorneys and the warden will check for any last-minute orders from Idaho Gov. Brad Little that would halt the execution. Little has previously said he does not intend to do so, and the U.S. Supreme Court denied Creech’s request for a stay Wednesday morning.

If it happens, the execution will be Idaho’s first in 12 years.

Barring any reprieve, volunteers with medical training will insert a catheter into one of Creech’s veins. He’ll be given a chance to say his last words and a spiritual advisor may pray with him. Then the state will inject a drug intended to kill him.

Creech, who has been convicted of five murders in three states and is suspected in several more, has been imprisoned since 1974. He was originally sentenced to death for fatally shooting John Wayne Bradford and Edward Thomas Arnold, who picked him up while he was hitchhiking. That punishment, however, was changed to life in prison after the state’s sentencing law was found unconstitutional.

Then, in 1983, he was sentenced to death for the murder of fellow inmate David Dale Jensen. Jensen was 22, disabled and serving time for a car theft when Creech attacked him with a battery-filled sock on May 13, 1981.

Jensen’s family members described him as a gentle soul who loved hunting and being outdoors during Creech’s clemency hearing last month. Jensen’s daughter was 4 years old when he died, and she spoke about how painful it was to grow up without a father, piecing together everything she knows about her dad from other people’s memories.

In court documents filed late last week, Idaho officials said Creech’s spiritual advisor would be allowed to place a hand on his shoulder during the execution. The Episcopal bishop won’t be allowed to hold his hand or make any noise once the drug is administered. Creech will also be allowed to wear a crucifix, and his wife will be seated in the witness area where he can see her.

Creech’s supporters have pushed to have his sentence converted to life without parole, saying he is a deeply changed man. Several years ago he married the mother of a correctional officer, and former prison staffers said he was known for writing poetry and frequently expressing gratitude for their work.

During his clemency hearing, Ada County Deputy Prosecuting Attorney Jill Longhorst did not dispute that Creech can be charming. But she said he is nevertheless a psychopath — lacking remorse and empathy.

Creech’s attorneys filed a flurry of late appeals hoping to forestall his execution. They included claims that his clemency hearing was unfair, that it was unconstitutional to kill him because he was sentenced by a judge rather than a jury and that he received ineffective assistance of counsel.

But the courts found no grounds for leniency. Creech’s last chance — a petition to the U.S. Supreme Court — was denied a few hours before the scheduled execution Wednesday.

In addition to the Idaho murders, Creech has been convicted of killing William Joseph Dean in Oregon and Vivian Grant Robinson in California in 1974. He was also charged with killing Sandra Jane Ramsamooj in Oregon that year, but the charge was later dropped in light of his other murder sentences.

In 1973, Creech was tried for the killing of 70-year-old Paul Schrader in Tucson, Arizona, but was acquitted. Authorities still believe him to be responsible and say Creech also provided information that led them to the bodies of two people near Las Vegas and one person near Baggs, Wyoming.

Creech’s execution will be the second in the U.S. this year, according to the Death Penalty Information Center. The first was in Alabama last month, when Kenneth Eugene Smith became the first death row inmate to be executed using nitrogen gas. Alabama officials said the method would be humane, but Smith seemed to remain conscious for several minutes and appeared to writhe in agony for at least two minutes.

Another execution in Texas is also scheduled for Wednesday. Ivan Cantu was sentenced to die for the fatal shooting of his cousin, James Mosqueda, and his cousin’s girlfriend, Amy Kitchen. Cantu has maintained he is innocent.

Idaho’s death penalty was established in 1864, about 26 years before statehood. Since that time, 29 executions have been carried out, according to the Death Penalty Information Center, including the state’s last hanging in 1957.

Executions became rare in the following decades. Though dozens of people have been sentenced to death since the 1970s, Creech will be only the fourth to be executed by the state since 1957 — all by lethal injection.

Keith Eugene Wells, 31, was executed in 1994 for the murders of John Justad and Brandi Rains committed in Boise four years earlier; he had given up his appeals and demanded to be put to death. Paul Ezra Rhoades was executed in 2011 for the 1987 murders of Stacy Dawn Baldwin and Susan Michelbacher in eastern Idaho. Richard Albert Leavitt was executed in 2012 for the 1984 murder of Danette Jean Elg in eastern Idaho.

After Creech’s execution, just seven people will remain on Idaho’s death row. A handful of those sentenced to death in the state in the past 50 years have died of natural causes, and at least two were exonerated. Many others have had their sentences reduced on appeal.

Earlier this year Idaho lawmakers considered adding the death penalty as a possible sentence for people convicted of lewd conduct with a child, but the legislation did not make it through the House of Representatives.