LOS ANGELES (AP) _ After preparing for 200 hours, attending a seminar on how to testify and being questioned by prosecutors for longer than anyone else in the O.J. Simpson trial, in the end the coroner could only say one thing for sure:

Nicole Brown Simpson and Ronald Goldman were stabbed and they bled to death.

The exact times of their deaths, the number of murder weapons, the number of assailants _ none could be determined within a reasonable degree of medical certainty, Dr. Lakshmanan Sathyavagiswaran acknowledged Wednesday under cross-examination.

``In fact,'' defense attorney Robert Shapiro said in an almost taunting tone, referring to the imprecise range for the time of deaths, ``all of your expertise lends you to the opinion that a lay person could give.''

When the coroner returns today for a ninth day of questioning, he will tie pummeled evidence technician Dennis Fung for length of time spent on the stand.

The defense immediately sought to shift attention away from the murders of Simpson's ex-wife and her friend _ as graphically illustrated to the jury in grisly autopsy photos _ and back to official foul-ups and the claim that Simpson was railroaded by overzealous authorities.

Although Lakshmanan admitted dozens of mistakes by his office and his deputy, Dr. Irwin Golden, Shapiro reached for one more, suggesting that the coroner's office didn't even measure Goldman's body properly.

The coroner's office listed Goldman at 5-foot-9. Over prosecution objections, Shapiro showed that Goldman's driver's license said he was 6 feet.

Repeatedly saying he had nothing to hide and that he is the first one to admit mistakes, Lakshmanan bristled at suggestions that his testimony had been useless.

``I don't think my eight days of testimony has been wasted,'' he told Shapiro. ``But if that's your perception, I can't change that.''

The coroner denied he was trying to cover up for Golden, who conducted the autopsies. But he acknowledged that he had never before testified in place of the examining pathologist unless the doctor was unavailable.

``Is Dr. Golden sick?'' Shapiro asked.

``No. He's still working in the coroner's office,'' Lakshmanan replied.

``Is he on vacation?''

``No.''

Lakshmanan said he thought both of them would testify, and he didn't know until Monday that prosecutors wouldn't call Golden as a witness.

The coroner noted that he had spent a large amount of time preparing for his testimony, some 200 hours, including work at home and two visits to the crime scene. He also said he was among county officials who recently attended a seminar by a trial expert on how to testify in court.

Shapiro suggested that prosecutors were trying to keep the spotlight off Golden because they were embarrassed about his mistakes and some of Golden's conclusions didn't agree with their theory of the crime.

Shapiro worked to weaken Lakshmanan's stated opinion that the same single-edged knife probably caused all of the stabbing wounds to both victims.

Firing questions in rapid succession, Shapiro asked if two single-edged knives could be involved _ the coroner said they could _ or if a single and a double-edged knife could have been used, or a combination of sharp-edged weapons. That too was possible, Lakshmanan said, although he insisted one single-edged knife was logical.

``Can you tell us as a doctor, as a scientist and as the chief medical examiner of one of the largest counties in the United States that ... you will put your reputation on the line that one single-edged weapon was responsible for all the injuries to both victims in this case?'' Shapiro pressed, his voice rising slightly.

``I can't say that,'' the coroner replied.

The defense also took aim at Lakshmanan's broad range for time of death. It stretched from 9 p.m. on June 12, 1994, to 12:45 the next morning _ and included times when both victims were known to be alive.

Earlier, anticipating the attack on the time estimates, prosecutor Brian Kelberg questioned the coroner at length about how time of death is established, the complications of taking a corpse's liver temperature and the differences between algor mortis, which is body cooling, and rigor mortis, or body stiffening.

``We can only give an estimated range,'' Lakshmanan said. ``We cannot give any precision.''

The coroner explained, however, that the range could be narrowed by taking into account such non-medical factors as the time the bodies were found, just after midnight; a phone bill showing Ms. Simpson's last conversation with her mother at 9:35 p.m. June 12; and witness statements that Goldman left work at 9:50 p.m.

Prosecutors contend the murders were committed about 10:15 p.m., based on a wailing dog heard by Ms. Simpson's neighbors. The defense contends the deaths could have occurred much later, perhaps while Simpson was en route to the airport for a red-eye flight to Chicago. He left his estate in a limo about 11:15 p.m. Simpson's attorneys say he was home alone when the murders were committed.

``Everybody knows (time of death) is an important issue in this case,'' said Loyola University law professor Stan Goldman. ``The more general the timeline, the better for the defense. ... By 11, O.J. Simpson has an alibi.''