CLEARWATER, Fla., June 13--State Attorney Bernie McCabe's weekend reading was a memo by his chief assistant urging him to drop the first criminal charges ever filed in the United States against the Church of Scientology.

The 31-page document was filled with medical words that McCabe had never heard, but its essence was all too clear: The star prosecution witness, Medical Examiner Joan Wood, really didn't know why Scientologist Lisa McPherson died in 1995 while in the care of Scientology staffers in Clearwater. It said she had botched the case beyond repair.

When McCabe arrived at his office Monday morning, he remained undecided. He read the memo one more time before the weight of its words finally sank in. Then, "I realized I had nowhere to go," he said Monday evening. "You just have to do the right thing and let the chips fall where they may." Just before lunch, the veteran prosecutor had written "OK" atop the memo with a scrawled note that instructed its writer, Assistant State Attorney Douglas Crow, to drop two felony criminal charges against the church's Clearwater operation: abuse of a disabled adult and practicing medicine without a license.

It was a quiet ending to a case that took police two years to investigate and prosecutors two years to prepare before it evaporated Monday just four months before the scheduled trial. Over that time, Scientology spent millions of dollars in its defense and felt the sting of its critics, who took to the Internet and spread the news of McPherson's death around the world.

They formed a Scientology "watchdog group" in the church's back yard in Clearwater. They began annual protests outside the Fort Harrison Hotel, the Scientology retreat where church staffers tried for 17 days to nurse McPherson through a psychotic episode before she died of a blood clot in her left lung.

One critic, millionaire Robert Minton, who moved to Clearwater to form the watchdog group, continues to finance a wrongful death lawsuit brought by McPherson's family against the church.

Stories about McPherson's death have appeared on major television networks and in newspapers across the world, damaging Scientology's recruitment efforts, even straining its hold on some existing members who questioned their church's role in her death.

Over time, the death of Lisa McPherson, who was 36, mushroomed into one of the major crises in Scientology's 44-year history--a problem so consuming many top church officials spent nearly all their time building a defense.

Although the civil case is still pending in Hillsborough County Circuit Court, McCabe ended Scientology's biggest headache--the criminal prosecution--with one stroke of his pen.

"It's not a celebration, I would describe it more as a sense of relief," said Marty Rathbun, a top church official who normally deals with ecclesiastical matters but in recent years has been thrown into battle as a defense strategist.

"It's a big milestone," Rathbun said. If anything good came of the case, he said, it was that it prompted Scientology to accelerate efforts to improve its relations in Clearwater.

Scientology's worldwide leader, David Miscavige, was in Clearwater on Monday but declined an interview request.

Crow, the assistant prosecutor, placed the blame squarely with Joan Wood, the veteran medical examiner, who in 1997 broke her usual practice of discussing cases only in court.

McPherson died on Dec. 5, 1995, after 17 days at the Fort Harrison Hotel. A group of Scientology staffers had taken her to a hospital 45 minutes away to see a fellow Scientologist working in a New Port Richey emergency room.

She was dead on arrival and Clearwater police began to investigate the next day. When the case became public in December 1996, church officials called the death an accident, said McPherson was at the Fort Harrison for "rest and relaxation" and was free to come and go.

Saying Scientology officials were misleading the public, Wood told local newspaper reporters and the TV show Inside Edition that McPherson was not given fluids for five to 10 days and was unconscious up to 48 hours before she died.

Scientology's own internal logs would later show that the church's initial characterizations were untrue, and that McPherson grew so weak while at the Fort Harrison she was unable to stand on her own three days before her death.

Still, Wood's early statements damaged her relationship with prosecutors, left her open to lawsuits from Scientology and painted her into a legal corner, Crow said in his memo to McCabe.

Crow described Wood's more recent statements on the case as "illogical," fluctuating and inconsistent. He questioned her memory and her judgment, adding her actions leave prosecutors unable to prove the case against the church beyond a reasonable doubt.

In the death certificate she issued in 1996, Wood said the blood clot that caused McPherson's death was due to "bed rest and severe dehydration." She listed the manner of death as "undetermined."

When the church asked her last fall to reconsider her conclusions, Wood reviewed thousands of pages of medical studies and consultant reports provided by Scientology. In February, she amended the death certificate, changing the manner of death to "accident" and leaving out the words "bed rest and severe dehydration."

Surprised, McCabe's office began its own review of the case, which was detailed in Crow's memo.

Among the issues he cites are the events leading up to Wood's decision to change the death certificate.

Wood initially changed it to read the death was an "accident" not caused by dehydration, Crow said. She then reconsidered, he said, deciding to re-insert dehydration as a cause of death and list the death as a homicide. The next morning, she changed her mind once again and finalized the changes.

Crow submits that several factors may have "impacted the quality of her judgment." He cited Wood's vulnerability to litigation in the case and a suggestion by Scientology that it could "reveal information extremely damaging to Wood's office and her career."

Crow was dismayed after a two-hour deposition of Wood on June 1, a transcript of which was released Monday. That document shows the state's case was on even shakier ground than he realized. It was clear that the state's chief witness had severe credibility problems.

Wood's recollection of events, actions and conversations was inconsistent. Her opinions seemed to change each time he asked her a question about why she made a decision. Wood admitted to him that she made a forensic error. She could not logically explain or justify why she decided to change the death certificate and kept equivocating on forensic issues in the case.

"The most recent statment given by Wood represents yet another decided shift in her opinion," Crow wrote. "She indicates she has doubts about the severity of Lisa's dehydration and testified that dehydration "may or may not' have been a factor in her death.

Among the problems he cited:

Wood did not do McPherson's autopsy personally but assigned it to Robert Davis, an employee who later was asked to resign and has become a witness for the church. He disputed Wood's conclusions and testified that she did not speak to him about her findings before signing his autopsy after he had resigned.

She admitted to Crow that, until shortly before she changed her findings, she never saw evidence of a bruise on McPherson's leg which could explain the formation of the blood clot behind her knee that is thought to have traveled to her left lung, killing her. She could not explain why she did not see this in previous examinations.

Wood could not recall details about the reasons she decided to change the death certificate nor details of her conversations with a fellow medical examiner who advised her.

Earlier this year, McCabe was one of several law enforcement officials in Pinellas and Pasco counties who recommended that Wood be allowed to serve another term. She was reappointed by Gov. Jeb Bush this spring to a term that expires in 2003.

Asked whether he would do the same today, McCabe paused and said: "I think the issues in this case were perhaps unique and I don't think that this case should be viewed as a measure for her overall situation." He added he would not favor any move to have Wood removed.

Ken Dandar, the Tampa attorney representing McPherson's estate in the wrongful death lawsuit, said of McCabe's decision: "This is a prosecutor that has no backbone."

He blamed the decision on politics, saying politicians "want everything to be quiet, nice and neat and going after Scientology is too raucous. . . . The people should be ashamed of their prosecutor."

In the civil case, Wood is "just another doctor," one of many medical experts, Dandar said. "This has absolutely no effect on the civil case. It actually makes our resolve stronger, if that's possible."

The church reacted to Dandar's statements, calling them inappropriate.

"The citizens of Pinellas County should be proud to have a state attorney who has integrity," said Rathbun, the church official. "The only political pressure was the other way (in favor of the prosecution)."