Prosecutors opened their case in the O.J. Simpson murder trial today by outlining in vivid detail what they called "devastating proof" that the former football star brutally slashed to death his ex-wife and her friend and then left a trail of blood that led directly to his own bedroom. After showing jurors graphic color photographs of the blood-soaked bodies of Nicole Brown Simpson and Ronald L. Goldman, lead prosecutor Marcia Clark asserted that "over and over and over again," genetic testing of the blood pointed to the inescapable conclusion that O.J. Simpson committed the murders. And she contended for the first time that blood found on a pair of socks in his bedroom matched blood of the victims.

Prosecutor Christopher Darden earlier had offered the motive: the jealousy of an abusive and obsessive ex-husband. "He killed Nicole for a single reason," Darden told the court. ". . . He killed her because he couldn't have her, and if he couldn't have her, he didn't want anyone else to."

Just as the defense team was about to respond in its opening statement, Judge Lance A. Ito abruptly halted the proceedings after learning that the sole television pool camera in the courtroom had inadvertently broadcast the face of one of the alternate jurors.

A furious Ito cut off the broadcast and told the courtroom he was considering terminating all television coverage for the rest of the trial. Defense attorney Robert L. Shapiro objected that it was unfair to allow the whole world to hear the prosecution's lengthy opening statements and then not allow equal coverage of the defense. Ito is expected to hear both sides on the issue, as well as hear representatives of the news media, and rule Wednesday.

It was a bizarre surprise ending to a day in which prosecutors sought first to undercut Simpson's public image as an affable and nonthreatening celebrity and then hammer home to jurors the evidence they said links him to the crime.

"On June 12, 1994, after a violent relationship in which the defendant beat her, humiliated her, after he took her youth, her freedom and self-respect, just as she was about to break free, Orenthal James Simpson took her very life in what amounted to his final act of control," Clark said, her voice quavering with emotion.

As Simpson watched intently, occasionally shaking his head, Clark disclosed for the first time that a bloody glove found by police detectives at Simpson's home shortly after the killings had not only blood and hair follicles that genetically matched those of his ex-wife and Goldman, but also fibers from Goldman's shirt and from Simpson's Ford Bronco.

Clark then presented the jury with a list of other blood test evidence that she said would prove Simpson had to have been at the scene of the crime. Simpson has pleaded "absolutely, 100 percent not guilty" to two counts of first-degree murder.

Clark said bloodstains lifted from the socks found in Simpson's bedroom genetically match his blood and that of Nicole Brown Simpson. She also revealed that police found a mixture of Goldman's and Nicole Simpson's blood inside and on the door of Simpson's Ford Bronco, and fibers from the car on a cap found at the crime scene.

Anticipating challenges to how the police collected the blood evidence, Clark said sloppy handling might, in some cases, lead to faulty test results. But, she said, the prosecution had attempted to determine from all the tests if Simpson could possibly be excluded, and "over and over and over again the answer was no, the defendant cannot be excluded." "This is not a game. This is about justice and seeing justice done," Clark said.

Preceding Clark, Darden methodically traced Nicole Brown Simpson's 17-year relationship with the former football star, an obsessively jealous and possessive relationship, Darden said, that was driven by O.J. Simpson's all-consuming need to control the victim.

While the public came to know Simpson as a congenial sports hero, football legend, screen actor and pitchman for the Hertz car rental company, Darden said, "it is not that public face that is on trial here today."

Behind the walls of Simpson's Brentwood estate and his ex-wife's nearby town house, Darden told the jury, the defendant presented another face, "the face of a batterer, a wife beater, an abuser, a controller" and "the face she encountered in the last moments of her life."

"You'll see the face of Ron and Nicole's murderer," he declared.

The June 12 murder of Simpson's former wife, Darden told the jury, was his "ultimate act of control" of her. Goldman, he said, became a victim simply because "he got in the way."

From the time the couple first met in 1977, when Nicole was a 17-year-old waitress and Simpson was a millionaire celebrity, he abused her physically and mentally, isolated her, dictated the way she dressed and controlled her financially, Darden said.

He said their relationship during and after their marriage was defined by cycles of "violence, apology, a period of calm, violence and apologies."

Darden outlined a series of violent incidents, beginning with a clash in 1985 when Simpson allegedly smashed the windshield of his wife's Mercedes with a baseball bat and including the New Year's Eve fight in 1989 in which the defendant pleaded no contest to a charge of spousal battery. He said that when Nicole filed for divorce in 1992, Simpson "couldn't deal with the loss of control. He couldn't let her go."

As Darden described a rejected and distraught Simpson who lost more than 20 pounds and repeatedly called his mother-in-law to "whine" about the breakup, the defendant turned in his seat and glared at Juditha Brown with what appeared to be a sarcastic smile.

Darden described how Simpson allegedly stalked his former wife, following her to restaurants and staring at her and, on one occasion, peering through her window to watch her having sex with a boyfriend.

As Darden described the alleged stalking, Simpson looked stunned, raising his eyebrows at one point and shaking his head before intently scribbling notes on a pad.

Finally, the prosecutor said, the couple's repeated attempts at reconciliation failed, and a few days after Simpson gave Nicole a bracelet on her birthday last May, she threw the gift at him and "let him know it was over. . . . She woke up to the true reality of their situation."

On June 12, while attending a dance recital of their daughter, Sydney, Simpson refused to talk to his former wife but sat near her, giving her "a menacing stare, a penetrating stare, an angry stare {that} made everyone uncomfortable," Darden told the jury. Being excluded that night from a Brown family dinner at the Mezzaluna restaurant, he said, was to Simpson a "reaffirmation that he was no longer in control." The murder later that night was "the final link in a progressive chain of abusive conduct and control." Clark, who shared the opening statement with Darden, presented the jury with a chronology that, she said, gave Simpson 70 minutes of unaccounted time to drive from his house to his ex-wife's town house, commit the murders and return home.

Clark said testimony will show that Simpson's houseguest, Brian "Kato" Kaelin, saw the defendant at his Rockingham Drive house at 9:35 p.m. and did not see him again until after 11 p.m.

She described how Allen Park, a limousine driver who had been called to take Simpson to the airport for an 11:45 p.m. flight to Chicago, arrived at the house at 10:45 p.m. She said that Park will testify that a few minutes later he did not see Simpson's Bronco in front of the house.

Clark cut short the end of her statement after Ito admonished her three times that the statement had become an argument.

Lead defense attorney Johnnie L. Cochran Jr. was set to launch his reply to the prosecution's case this afternoon when Ito called a halt to the proceedings. The visibly upset judge disclosed that at least one alternate juror, seated in the front row to the right of the prosecutors because of a lack of space in the jury box, had been shown inadvertently on camera. Ito then threatened to end televised coverage of the trial.

Shapiro said later the defense would prefer to have its opening statements televised, and then terminate coverage. Simpson's "right to a fair trial has been interrupted," Shapiro told a news conference later.

Cochran said it was "terribly unfair" to interrupt the proceedings before the defense's response to the prosecution's statements, which he characterized as full of "half-truths and not the total facts."

Court TV, the cable network operating the pool camera, informed Ito of the problem during the break following the prosecution's statements.

Under Ito's rules, the 12 jurors and 10 alternates have not been publicly identified by name, and their faces are not to be televised or artistically depicted in an effort to preserve their privacy. The jurors are visible to reporters in the courtroom.

Earlier, before the jury had been brought into the courtroom, Clark objected vigorously to Simpson's planned exhibition of old football injuries before the defense's opening statement, calling it a "blatant attempt to impress the jury with his charisma and star appeal."

Noting that on the morning of the killings Simpson had played golf and that he recently made an exercise video, Clark said his claims of physical disabilities would be made without having laid a proper legal foundation. Ito ruled that Simpson could show jurors the injuries but would not be permitted to make a brief statement of his innocence to the jury as the defense had requested. CAPTION: EVIDENCE FOUND AT O.J. SIMPSON'S MANSION (This graphic was not available). CAPTION: THE CRIME SCENE (This graphic was not available). CAPTION: THE DEFENSE O.J. Simpson, flanked by defense attorneys Johnnie L. Cochran Jr. and Robert L. Shapiro, listens to the prosecution deliver its opening statements in his murder trial. CAPTION: THE PROSECUTION Prosecutor Christopher Darden addresses the jury during his opening statement. He said O.J. Simpson killed Nicole Brown Simpson "because he couldn't have her."