As time ticks away for condemned killer John Frederick Thanos, the last moments of his life are following a 36-page script -- a death manual written by Maryland corrections officials.

It details everything from the moment prison officials received his warrant of execution to the disposal of Thanos' body and possessions. It's a hour-by-hour account of how Maryland officials will carry out their first execution in 33 years, and the first ever by lethal injection.

Thanos has refused to appeal his sentence, and the courts last week rejected the final appeals brought on his behalf against his will. That means that the execution could occur as early as midnight tonight.

Only two possibilities remain that could prevent the execution -- Thanos opting to file a federal appeal himself or intervention by Gov. William Donald Schaefer. Neither is considered likely by those familiar with the case.

"I'm told, for the record, that he [Thanos] is very much at peace with himself," said Leonard A. Sipes Jr., director of public information for the Department of Public Safety and Correctional Services. "He's not causing any problems whatsoever within the prison. He seems very much at peace with himself and his decision."

The details of the execution are contained in a policy manual, labeled "Highly Confidential," that became a public record last week when it was introduced as evidence at a court hearing for death penalty opponents who argued that the procedures are flawed.

In an unsuccessful attempt to stay the Thanos execution, American Civil Liberties Union attorneys argued that the procedures present a serious risk that the execution will be botched and Thanos will suffer unnecessarily.

They argued that the "execution team" that will carry out the death sentence does not have the proper training to administer an intravenous (IV) needle. Thanos could be subjected to repeated jabbing as corrections staff struggle to find a vein, the lawyers argued.

If that happens, no one outside the prison system will know. According to the execution manual, the procedures are designed to make sure that witnesses won't see Thanos until after the intravenous needles have been inserted.

The ACLU also argued that if the drugs are mistakenly injected into tissue, instead of directly into the bloodstream, Thanos could be conscious, paralyzed and awake while he slowly

suffocates.

A Baltimore City Circuit Court judge ultimately disagreed with the ACLU and rejected its request for an injunction to stop the execution. On Friday, Maryland's highest court refused to intervene.

So the clock continues to tick, and corrections official continue to follow the script that will send Thanos to his death for the 1990 murder of Gregory Taylor, 18, of Hebron.

Thanos is also under a separate sentence of death for the murders of two Baltimore County teen-agers, Billy Winebrenner and Melody Pistorio.

Maryland officials are bound by law to keep the time and day of the execution secret and will announce the execution only after it occurs.

The hour of the execution was chosen more than a month ago, according to the manual, but the witnesses, as many as 12, will not be informed of the time or summoned until three hours before it happens.

The execution could take place any time from midnight tonight through midnight Saturday, and Thanos himself will not know until an hour before the execution.

By then, he will be in a 7-by-8-foot cell in the death house, a row of four cells next to the death chamber -- the area of the Maryland Penitentiary where his execution will take place.

Through a doorway is the 300-pound lethal injection table, a steel rectangle covered with vinyl padding and with leather straps attached.

In the seven days before execution week, according to the manual, daily "noncontact" visits to the condemned prisoner were allowed between 1 p.m. and 7 p.m. Family, friends and clergy have been to see him, said Mr. Sipes, the prison system spokesman.

Five days before execution week, the manual says, the "execution commander" selects his "execution team," a 10-member squad that will do everything from monitoring the phones to inserting the deadly drugs into one of Thanos' arms.

Phone lines in the chamber, including a direct line to Governor Schaefer, who has authority to stay the execution, have been checked and rechecked. The governor does not intend to stop the execution, said Page W. Boinest, his spokeswoman.

The equipment used in the execution is tested tested and retested. A checklist of equipment and supplies is reviewed 96 hours before the execution by the execution team. The list includes the three drugs that will be administered, along with syringes, tape, two IV poles, surgical masks, scissors and even a flashlight with batteries.

Four days before the execution, Thanos is asked to give instructions for his funeral arrangements. Thanos has already requested that his body be donated to science.

Three days before the execution, sealed envelopes containing the date and time of the execution are hand-delivered to Governor Schaefer, Bishop L. Robinson, secretary of public safety and correctional services, and Richard Lanham, commissioner of corrections.

The witnesses also are notified in writing of their selection.

The day before the execution, officials will take an inventory of Thanos' personal property in his presence, store it and ask him how he wants it disposed of.

Three hours before the execution, witnesses will be notified and told to go to a meeting place. From there, they will be driven to the Maryland Penitentiary to await the execution.

In his cell, Thanos will get a final meal, but it won't be anything special -- just whatever is on the prison menu that day. Thanos may choose to have a chaplain or priest with him his last few hours.

As the execution nears, special guards will escort Thanos to the death chamber. Members of the execution team will strap Thanos to the table, and a heart monitoring device will be attached.

A volunteer doctor will monitor, but not participate in, the execution.

Two bags of nonlethal intravenous fluid will be positioned on two IV poles, one for each arm. Execution team members then will insert an IV needle and start a fluid drip into each of Thanos' arms. This will ensure that the execution can proceed if one of the two IVs doesn't work properly.

Witnesses will be brought into the area only after the fluids are flowing into Thanos' arms, but before the lethal drugs are injected.

Before the lethal drugs are inserted into the IV, Thanos will be asked once again if he wants to pursue further appeals, according to Gary E. Bair, an assistant attorney general. If he does, the execution process would be stopped immediately.