Ito said FBI agent Douglas Deedrick would be allowed to tell jurors that the fibers could have come from the same source. But he barred the agent from presenting detailed evidence on the rareness of the tan carpet, which his report said was installed only in Ford Broncos manufactured in late 1993 and early 1994.
Ito, who seemed pained by his own decision, said Deedrick's research showed ''how relatively few Ford Bronco automobiles there could possibly be . . . registered in the county of Los Angeles that would have this carpet fiber."
"This particular formula and this particular color - that's very compelling circumstantial evidence," Ito said. "I mean, it really narrows it down to where this carpet fiber came from."
But Ito said Deedrick had failed to give the defense a report on his findings until yesterday, on the eve of his testimony, violating state law and leaving the defense at an unfair disadvantage.
Prosecutor Marcia Clark pleaded with Ito to allow the evidence, contending that she had not known about the research until yesterday.
"To preclude evidence that is important to the proof of the elements of the crime would unfairly punish not just the victims but the people of the state of California (and) . . . the families of Ronald Goldman and Nicole Brown Simpson," Clark said. "If the court feels that we have been remiss, then I would urge the court to penalize us personally, myself personally. But please don't, please don't penalize the proof of the case."
Ito, however, had little choice after defense lawyer Johnnie Cochran Jr. stood and quoted the judge's vow earlier in the trial to preclude evidence if either side again violated discovery rules.
Saying, "I'd like to quote from a wise judge," Cochran cited Ito's previous warning and added triumphantly, "I cited you Ito on the law!"
Besides flattering the judge, Cochran angrily bashed prosecutors during a fiery oratory in which he actually shouted himself hoarse and had to pause for a sip of water.
"This is more than a mistake," Cochran said of the prosecution failure to disclose Deedrick's findings. "This was calculated. This was intentional. This was a tactical decision to try to gain an advantage . . . because their case was going poorly.
"They thought they were losing," Cochran said. "They had to . . . try to pull something . . . as the case whimpers to a conclusion."
The flap erupted during an informal meeting Wednesday after court, when Deedrick gave defense lawyers a one-page, handwritten summary of his findings.
After questioning the agent more closely, defense lawyers called for Ito, who ordered Deedrick to disclose his research notes, along with a more detailed report titled, "The Search for the Source: Carpet fibers found on the leather glove and the knit hat in the O.J. Simpson case."
Cochran said the report contained surprising information about the limited number of vehicles equipped with the carpet. Those details, Cochran said, had been denied to a defense investigator when he questioned a representative from the Masland Co., the carpet maker, earlier this year.
"When the FBI calls Masland, it's far different than the defense investigator calling Masland," Cochran said. "Masland gives us disinformation, saying this carpet was common - common, not rare."
Deedrick defended his decision not to share the material earlier, saying, ''I don't consider it a report," but rather "a narration of my investigation."
But Ito didn't buy it. "I don't care what you call this," he said, waving the document from the bench. "This is a report."
In addition to his carpet analysis, Deedrick is expected to testify that blue-black fibers, possibly from the killer's clothing, were found on Goldman's shirt, on Nicole Simpson's slashed throat, and on the bloodstained socks and leather glove found at Simpson's mansion the day after the murders.