-- John J. Geoghan, the former priest and convicted child molester killed in a Massachusetts prison Saturday, was followed into his cell just after lunch by a fellow inmate who bound and gagged him before strangling him with a bed sheet, according to a union representative for prison guards.

The attacker, whom authorities identified as Joseph L. Druce, jammed the electronically operated cell door to prevent guards from opening it. He tied Geoghan's hands behind his back with a sheet and gagged him. He then repeatedly jumped from the bed in the cell onto Geoghan's motionless body and beat the defrocked priest with his fists.

Only one correction officer was on duty in the protective custody unit at the time, according to an account of the attack provided by Robert Brouillette, an executive of the Massachusetts Correction Officers Federated Union, who interviewed correction officers for seven hours Saturday. State and county officials involved in the investigation would not comment on Brouillette's description.

Druce entered Geoghan's cell just before noon, Brouillette said, when the prisoners left their one-person concrete cells to return their lunch trays. The solid cell door has a chest-high window that guards can look through as they pass by. When the officer on duty heard noises coming from Geoghan's cell but could not open the cell door from the control panel at his station, other officers were summoned by walkie-talkie. It took several of them to pry open the door.

"It was pretty clear when they got in there that [Geoghan] wasn't going to wake up," Brouillette said.

The 68-year-old former priest, who was being held in a protective custody unit with 23 other inmates, ostensibly to keep him safe from the general prison population, was taken by ambulance to a hospital and pronounced dead at 1:17 p.m. An autopsy will be performed Monday.

Druce, 37, was immediately isolated and will be charged with murder, investigators said. Massachusetts does not have a death penalty, so it is unclear what additional punishment he could receive since he is serving a life sentence for strangling a man in 1988. He also was convicted while in prison of attempting an anthrax scare by sending envelopes filled with white powder and covered in Swastikas to about 30 Jewish lawyers nationwide in 2001.

The Worcester County district attorney's office said that Druce was born Darrin Smiledge but changed his name while in prison. Druce's father, Dana Smiledge, told the Boston Globe that his son hated Jews and blacks and had a grudge against gays.

Dana Smiledge also told the Globe that he had not spoken to his son in eight years and wanted nothing more to do with him, saying, "I did everything I could do for years to help him. He deserves to stay in prison."

Smiledge's brick and stone home is set well back from the street on a manicured lawn in Byfield. A sign next to the front door advises: "Live well, laugh often, love much," but there was no laughter in the house today. "I'm not talking to anybody," Smiledge said.

Across the state, while few people outwardly mourned the passing of a man who sparked a scandal in the Roman Catholic Church and was alleged to have molested nearly 150 children -- mostly boys -- while a priest in a number of Boston-area parishes, the question was: How could this have happened?

"When you have someone in prison who is as infamous as John Geoghan, it's absolutely predictable that people will prey upon him, and it's the Department of Correction's job to keep him safe," said Leslie Walker, a lawyer and the executive director of Massachusetts Correctional Legal Services, a private nonprofit group that provides legal services for indigent prisoners. Geoghan was one of her clients. "They failed miserably. He was a frail old man, and he should have been kept safe."

A Department of Correction spokeswoman said that a staffing analysis is "conducted on a regular basis at our facilities, every other year, and all facilities are staffed at a safe level." She said she was not sure when the last analysis was conducted at Souza-Baranowski Correctional Center in Shirley, 30 miles northwest of Boston, where the attack took place.

But some politicians and correction officers said they hoped that the brutality of the attack and the high profile of the victim would shed light on understaffing in state prisons, which they said is becoming a serious problem.

"We've cut about $3 billion out of [the state's] budget in the last three years, and that may mean police and corrections aren't as well staffed as they should be," said state Rep. Martin J. Walsh (D), the chairman of the legislature's homeland security and federal affairs committee. Last year, he and another legislator helped block the firing of 51 correction officers statewide.

"It should be of the utmost importance to ensure that not only are prisoners safe, but that guards, janitors and others who work in these places stay out of harm's way," Walsh said.

Brouillette said the incident "should wake some people up about what we've been saying for years. There are not enough correction officers. The prisoners know the schedule well, they know when only one guy is on duty and they can take advantage of it."

Souza-Baranowski, a maximum-security prison named for two correction officers who were killed at another prison, opened in 1998 and has seen its share of violence. Guards have been beaten and stabbed, leading to retribution on prisoners.

In 2001, 10 guards were injured at Souza-Baranowski -- including one whose skull was fractured -- in a lunchtime melee touched off when one guard was struck in the face with a dining tray. Later that year, correction officer union representatives picketed outside the prison to try to encourage the hiring of more guards.

Brouillette, whose union represents about 5,000 officers, estimates that the facility is "70 or 80" correction officers short of being fully staffed, and that one section of the prison, which had been used to segregate inmates who had fought, is closed because there are not enough staff members to operate it. Overall in the state, he said, about 300 additional officers are required to maintain adequate safety.

Walker, the inmate advocate, said that staffing concerns were just an excuse. "There's a culture of violence in these places that allows and even encourages these things to happen," she said, noting that the state's prison population of 21,000 had declined in recent years. She said she hoped that the U.S. attorney's office would conduct its own independent investigation of the incident.

An investigation by the Worcester County district attorney's office and supported by other state agencies would seek to determine whether inadequate staffing played a role in Geoghan's death, said David Shaw, a spokesman for the Massachusetts Department of Public Safety, which oversees prisons. The district attorney's office did not return repeated telephone calls today.

It is still unknown whether Geoghan and Druce had had any previous altercations in prison, or whether they were acquainted before their incarceration.

"We may not ever find out why this happened, but it is not secret that [child molesters] are considered the lowest of the low in prison," said state Rep. Demetrius J. Atsalis (D). "They are considered targets."

A Massachusetts Department of Corrections officer guards the prison in Shirley, Mass., where defrocked priest John J. Geoghan was killed by another inmate on Saturday. Geoghan was a central figure in the Roman Catholic Church's sex abuse scandal.Joseph L. Druce, left, shown in 1986, who is serving a life sentence for a 1988 murder, is the main suspect involved in the killing of convicted child molester John J. Geoghan, above, his fellow inmate.