Students of homicide sometimes say there are two forms of the crime: murders that fascinate and murders that horrify. The trial of O.J. Simpson is a classic version of the former. The reams of print, the hours of broadcast, the millions of dinner party conversations focus not just on the question of guilt or innocence, but on Simpson's character, his seemingly tragic flaws, his rise and fall, his expensive defense, his prosecutor's hairdo. People are not reduced to tears by the Simpson trial -- who would cry over a spectator sport?

In Canada, a shatteringly clear example of the second kind of murder trial is unfolding. Paul Bernardo, a 30-year-old former bookkeeper, is charged with kidnapping, raping, torturing and killing two teenage girls in 1991 and 1992. He recorded on videotape the gruesome preludes to the alleged executions; also on those tapes are the girls' screams, cries and pleas for their lives. Those tapes have been played in the courtroom.

Observers react to the Bernardo trial in only one way, with horror. No one debates what is true about the charges against him, what his motivations might have been, whether the police bungled the investigation. There is some disagreement over what the public should and should not know about the gruesome evidence, and the role of one key player remains unclear. But the public response during the seven weeks the trial has been underway has been almost purely visceral.

"O.J. Simpson might have been jealous, but this is nothing like that. This is psychotic," said Heiwete Girma, 16, as she waited in line in 90-degree heat for one of the 100-plus public seats at the trial. By the time she entered, she had waited for 32 hours. Girma was one of hundreds of young girls who have attended.

The two trials really only have three common elements: The nations in which they are occurring are fixated on them. Two victims were murdered in each. And in each case, a large dog apparently witnessed the crimes.

The differences are more plentiful. Where Simpson is a longtime public figure, Bernardo is known only for his alleged crimes (in addition to the two murders, he is charged with the manslaughter death of his ex-wife's teenage sister and with numerous rapes). Where Simpson is accused of killing out of passion, Bernardo is charged with killing from calculated perversion. Simpson is charged with killing his ex-wife, while Bernardo's then-wife was his accomplice (how willingly she assisted him may become clearer now that she is on the witness stand).

And the contrasts reach beyond the crimes. The judge in the Bernardo case is completely in control of the jury, whose members are bound for the rest of their lives not to discuss the case publicly. The jury is not sequestered, though there are a few restrictions on media coverage.

No books about the case have been published (though at least four are in the works). Articles and television reports about the case are plentiful, but opinions and analysis in the media are not. The defense is taxpayer-funded and relatively cheap. The trial itself is not broadcast on television, though broadcast booths have been constructed across the street from the courthouse, and correspondents give breathless reports several times a day.

Television viewers and newspaper readers in the United States have heard or read nearly every word spoken in the courtroom in Los Angeles. The details of the acts Bernardo is accused of performing are so horrible, so cruel, so bestial that the media do not reveal everything they hear, even though it is legal to report almost everything that is said before the jury. And the articles and broadcasts that do appear are so disturbing they are usually preceded, in print or on the air, with a warning that children should not be exposed to this information.

Court stenographers in the Simpson case pose for happy pictures in People magazine. The anonymous stenographers in the Bernardo trial cover their faces with their hands in court as the incriminating videotapes are played, to hide their emotions.

"I must say, I have a lot of trouble intellectualizing the Bernardo trial, I find it so disgusting and bizarre," said one Canadian law professor who -- in a request rarely heard in Los Angeles -- asked not to be named for fear he would appear to be exploiting the case. "I really don't know what so say about it, I feel such a deep sense of revulsion." The Victims

Early on the morning of June 15, 1991, in the small town of Burlington, Ontario, a slim, blond 14-year-old girl named Leslie Mahaffy disappeared. She had been out late with friends after the funeral of another friend who had been killed in a car crash. Mahaffy's body was discovered two weeks later. She had been cut into 10 pieces and encased in concrete blocks, which were thrown into a lake. Investigators found that she also had been raped and beaten.

On April 16, 1992, 15-year-old Kristen French, a student at the Catholic academy in nearby St. Catharines, didn't come home from school. Her nude body, brown hair crudely chopped off, was discovered two weeks later in a ditch some miles away. She too had been sexually assaulted and savagely beaten.

Nine months later, police arrested Bernardo, an unemployed accountant. Three months after that, they charged him with the two murders. A month before his arrest, his young blond wife, Karla Homolka, eyes blackened from repeated beatings, finally had walked out on him and their black Rottweiler, Buddy. Her first stop was her parents' home in St. Catharines; her second was the police station.

Not only did she implicate Bernardo in the murders and rapes, she said a third death, previously thought accidental, had been caused by him, with her help. It was the death of Karla's younger sister, 15-year-old Tammy Homolka, who had choked to death on her own vomit, it was ruled at the time, on Christmas Eve 1990. But in fact, as it was stipulated at Karla Homolka's manslaughter trial in the summer of 1993, Tammy actually died after being drugged with anesthetic and sleeping pills so that Paul and Karla could have sex with her.

For nearly two years after Homolka's trial, the public knew almost nothing of the admissions she had made about her role in the three deaths, and of her accusations that Bernardo had forced her to drug Tammy and had killed Mahaffy and French. Nor did the public know that many of these activities -- though not the murders -- had been videotaped by Bernardo and Homolka.

Homolka's admissions, part of her plea bargain along with her promise to testify against Bernardo, were kept secret under a court-imposed publication ban designed to ensure that Bernardo received a fair trial. While Homolka began serving her 12-year sentence, much of the banned information was circulated on the Internet and in the foreign media, but was not published here. Bernardo's trial was moved to Toronto from St. Catharines to help ensure an impartial jury, which was efficiently selected in one week in early May. And then the revelations began. Hybrid Justice

The Canadian justice system is something of a hybrid between the British and American systems. Judges and lawyers wear robes (but no wigs). The judge, a red sash across his chest, is treated with the strictest deference. At the Bernardo trial, gray-haired Ontario Court Associate Justice Patrick LeSage, 59, presides from a bench raised about six steps above the level of the spacious courtroom. While court is in session, court officials, lawyers, members of the public and even reporters bow to him as they enter or leave the room.

In perhaps the most glaring contrast with the Simpson trial, Bernardo's defense costs less than $1,000 a day. It is funded by the government: Instead of putting public defenders on salary, Canada pays private lawyers to do defense work for the indigent. For this relative pittance, Bernardo gets two of the top criminal defense lawyers in the province of Ontario, John Rosen and Tony Bryant. They are working for about 25 percent of what they would charge a wealthy private client.

"It's the best system in the world," said Bryant. "It permits people to actually be defended." In contrast to an American public defender, he said, "John Rosen and I are not pressured by 500 other cases."

The system also shows considerable respect for the 12 jury members. During the selection process they were asked relatively little of what they knew about Paul Bernardo; much more than American jurors, they are expected to use judgment rather than ignorance in considering the evidence. They are not sequestered. They go home to their families every day, presumably eating dinner and playing with their children and trying to ignore media reports about the horrors they heard that day.

Early on, LeSage turned down a request by the Canadian Broadcasting Corp. to televise the trial. Certain elements of the trial, such as courtroom proceedings that take place outside the presence of the jury, cannot be reported in the print media or on television. Reporters are also prohibited from expressing excessive opinion about the case.

Alan Young is, as far as he can tell, Canada's only legal commentator on TV for the Bernardo trial. He was hired by CTV, the largest private network, to provide expert analysis, and he dutifully attends the trial nearly every day. But given Canada's stronger controls over trial coverage, he is hardly Greta Van Sustern.

"I'm there to explain the legal process. But unfortunately I have to be so cautious that at the end of the day there's not a lot left for me to talk about," he says. The Awful Evidence

The Bernardo trial has two high-drama elements that the Simpson trial does not: An eyewitness to the alleged crimes and videotapes that, prosecutors say, show the victims being beaten and raped by the accused.

A few people in North America have videotaped some or all of their criminal acts, but Canada has seen nothing to compare with the Mahaffy and French tapes, or the one of an unconscious Tammy Homolka being sexually assaulted by Bernardo and Karla Homolka. The press and public in the courtroom can hear the soundtracks from the videotapes, which have been played several times each, but they cannot see them. All the media can watch are the impassive faces of the jurors and the lawyers as they watch the videotapes.

By now, too, all of Canada has come to know the families of the victims. Who in Toronto can look at Karel and Dorothy Homolka, who attend when Karla testifies, without remembering that their oldest daughter has admitted she helped kill their youngest?

Every time Debbie Mahaffy walks with dignity into the courtroom, others present remember why she is here and wonder how she can bear it: The reason her daughter Leslie was wandering around her own back yard in the early hours of June 15 is that, because she missed curfew, her parents had locked her out of the house and she was afraid to knock.

And who could fail to notice Doug and Donna French, weeping silently as prosecutor Raymond Houlahan said in his opening statement that Kristen had tried to defy Bernardo? She told him when he ordered her to perform a particularly degrading act that "some things are worth dying for."

The videotapes, or at least the audio tracks of the videotapes, reveal a depth of sadism and perversion rarely seen or heard anywhere. In one scene, according to testimony from the police officer who made transcripts of the tapes, Kristen French is sodomized by Bernardo as she begs for forgiveness.

"I'm sorry. I'm sorry, I'm sorry, I'm sorry," French cries at one point. "You're my master and my boyfriend and the king."

"Most powerful," says Bernardo.

"You're the most powerful man in the world."

Then she asks, "Can I go to the bathroom after this?"

Bernardo: "{Expletive} you."

Similarly, Leslie Mahaffy begs Bernardo to let her go home so she can see her parents and her younger brother again. Blindfolded, she swears she will never reveal his or Homolka's identity. Hands bound with rope, she too screams and whimpers, crying "oh, please" as Bernardo apparently hurts her. Homolka said Bernardo decided Mahaffy could indeed identify him, and strangled her with an electrical cord about an hour after the last videotape of her was taken.

As the tapes were played, Bernardo, pale, tall and broad-shouldered, dressed in a double-breasted suit, watched intently on his own monitor. Only an occasional tightening of his jaw and facial muscles betrayed any emotion.

Where was Karla Homolka during all this taping? By her own admission, she was operating the video camera when she wasn't in front of it. And at one point, having given Mahaffy sleeping pills before her strangling, Homolka handed her a white teddy bear and told her, "It's okay." In court, Homolka said: "I didn't want her to feel any pain." Enigma on the Stand

As Karla Homolka testifies, she holds her chin down and rolls her eyes up at the prosecutor in a posture of submissiveness. A box of tissues sits near her. As a local newspaper columnist pointed out, she uses them whether or not she is crying. When she speaks of her sister, Tammy, she gets the same catch in her throat every time. The eye makeup and red lipstick she wore to her own trial two years ago are gone, as are the fluffy bangs. She wears plain suits.

The role of Karla Homolka is the enigma of the Bernardo case. She is an ambiguous figure in the same way O.J. Simpson is. Where Americans disagree about Simpson's possible guilt or innocence, Canadians feel no need to debate whether Bernardo committed the crimes of which he is accused. Instead, they ask each other whether Karla Homolka was a sex killer or a battered, enslaved wife.

"She's the fascinating element in the case," said D'Arcy Jenish, who is covering the trial for Maclean's magazine.

Homolka, now 25, says she was the virtual captive of Bernardo, whom she met when she was 17, married at 21 and divorced at 23.

"I was his little slave," she said in court. "I did things for him, got drinks for him, ironed his clothes for him, did sexual acts for him."

Among the things she said Bernardo had forced her to do was wear Tammy's clothing while having sex with him after Tammy died and pretend, after Kristen and Leslie died, that she was one or the other of them while having sex with him. She also says Bernardo made her find young girls to kidnap. Kristen French, for instance, was lured to approach Bernardo's car in a church parking lot by Karla, sitting in the car and asking for directions.

There is another view of Karla Homolka, one Bernardo's defense lawyers are expected to propound when Homolka's cross-examination begins tomorrow. They likely will try to show that the heavily made-up young woman smiling and laughing on the videotapes was more than an unwilling accomplice, that she aided Bernardo out of the same kind of perversion the prosecution contends led him to kidnap and kill.

Why did she not allow Kristen French to escape during the two occasions she was alone with the girl in the house, they may ask. Why does she wave and blow kisses to the camera while Bernardo is filming? How could she roll over and go back to sleep when Bernardo woke her and said he had kidnapped a girl and brought her home? Why was one of her first waking thoughts to keep that girl, Leslie Mahaffy, away from the telephone?

Perhaps these questions will be answered when Bernardo's lawyers have their turn. More likely, Canadians will never know Karla Homolka's true role, just as Americans may never know the full story of O.J. Simpson. Bureau researcher Moira Daly contributed to this report. CAPTION: Paul Bernardo (pictured in 1993) is on trial for the gruesome murders of Kristen French, bottom left, and Leslie Mahaffy, center. His ex-wife, Karla, bottom right, not only implicated him in the crimes but admitted to taking part.

CAPTION: The accused: Paul Bernardo in police custody in the summer of 1993.