A jury of seven Marine Corps officers at the Quantico Marine base found Cpl. Lindsey Scott not guilty yesterday on charges of attempted murder, rape, sodomy and abduction, concluding a marathon personal and legal struggle for Scott nearly five years after it began.

As Col. Donald Festa, the senior-ranking juror, read the verdict after 10 hours and 20 minutes of deliberation, Scott's stony demeanor broke for the first time since his second court-martial began Jan. 25. Tears welled in his eyes as his attorneys embraced him.

In the tiny spectators gallery, Scott's ailing mother, Mildred, began to shout in a gravelly voice, "Thank you, Jesus! Thank you, Lord Jesus! Thank the Lord for giving me back my innocent child!" before she was pulled from the courtroom by four or five supporters.

Civil rights activists pounded Scott's back and friends and relatives hugged him. Scott, 32, who spent four years behind bars in a federal penitentiary as a result of his conviction in his first trial in 1983, wept silently, evidently unable to speak.

In news conferences, Marine prosecutors and defense lawyers agreed that questions surrounding the victim's identification of Scott as her attacker were probably the key factor in the jury's decision. On the second day of the trial, the chief military investigator in the case testified that the woman told him five days after the attack that she "didn't get a good enough look" at her assailant to identify him positively.

Under military law, Scott needed the votes of at least three of the seven jurors to be found not guilty.

Reached by telephone at home, senior juror Festa would not comment on the substance of the jury's deliberations, but he characterized them as "very businesslike, but thorough." He added, "I think military justice prevailed."

The woman who accused Scott could not be reached at her parents' home in Rochester, N.Y. Her mother said, "We're making no statement at all."

Scott, speaking to reporters a half-hour after the verdict, said: "I maintained my innocence from the beginning. It was proven today by a jury of my peers that I was innocent . . . . I'm innocent. I'm free."

He said "my feelings about the Marine Corps have never changed. They're the best fighting force . . . " and he said he received a "very fair trial" under the military justice system that his backers and family had roundly denounced as racist and inept.

Scott is black, his accuser is white, and suggestions of racism in the military's investigation and prosecution of Scott have dogged the case since shortly after Scott became a suspect in the brutal 1983 attack. One member of the jury is black.

Despite his time in the federal penitentiary at Fort Leavenworth, Kan., at hard labor, Scott displayed just one momentary flash of bitterness, when he was asked what he thought of people who believe he is guilty. "I don't care what they think," he said.

He would not speak about his personal or professional plans. His father, James Scott Sr., said the family planned to attend church.

Prosecutors said the investigation into the attack on the wife of a young military policeman on April 20, 1983, will not be reopened. "The issue is definitely dead," said Maj. Ron M. McNeil, the lead prosecutor.

Scott's next step is most likely to come in the $1 million malpractice lawsuit that he has filed against the civilian attorney whom he selected from the Yellow Pages to represent him at his 1983 trial.

The conviction in that trial and Scott's sentence of 30 years at hard labor were set aside last summer by the nation's highest military appeals court, which ruled that the lawyer, Ervan E. Kuhnke Jr. of Dumfries, had not provided a competent defense.

"Ervan Kuhnke is probably the only person in the world who is as depressed today as Lindsey Scott is gleeful," said Scott's attorney Stephen G. Cochran.

Kuhnke, reached at his law office, said: "I won't make any comment. He's suing me."

After the appeals court ruling last July, the commanding general at Quantico, Lt. Gen. Frank E. Petersen, decided Oct. 22 to convene a second court-martial.

At the time, defense lawyers and military sources acknowledged that little had changed since the first trial, with one significant exception: the emergence of a former Zayre store detective who said she had seen Scott shopping in Woodbridge, about 12 miles from the marine base, at the exact time the woman said she had been abducted. That buttressed Scott's contention that he had spent the evening shopping for a present for his wife's birthday, which was the following day.

In the first trial, Cynthia K. Ausby, the former detective, said she recalled seeing Scott but was unsure of the date. She said after that proceeding that her memory had been jogged by reviewing store records.

Despite that new testimony, prosecutors and defense attorneys speculated yesterday that the key to the verdict was not the alibi, but the victim's doubts in her early efforts to identify the attacker.

In the days after the attack, the victim twice identified Scott as her assailant, first from a group of photographs, then from a lineup, but each time she equivocated, saying other men in the groups resembled him. In the lineup, she said she picked Scott because "he scares me the most." In neither session was she as certain as she later was in court, when she pointed across the courtroom to Scott, identifying him as the attacker.

At no time did she mention having noticed Scott's prominent gold front tooth -- a point Scott's lawyers made again and again.

Gary R. Myers, one of Scott's attorneys, yesterday called the woman's shaky identification of Scott "the hurdle that the jury simply could not overcome."

Another of Scott's lawyers, John F. Leino, agreed, but added, "It helps to have an innocent client."

Scott became a suspect -- and a cause celebre among such civil rights groups as the NAACP and the Southern Christian Leadership Conference -- soon after the victim was found bleeding and dazed in a remote spot on Quantico base.

The woman, then the 23-year-old wife of a military policeman who worked with Scott, told investigators that she had been lured from her apartment by a telephone call from a man who said her husband had been in an accident and who offered to take her to the hospital.

Instead of going to the hospital, the man drove her to a wooded area, sodomized and raped her in his car, then led her into the woods where he choked her and slashed her throat, the woman testified.

Neither the specific site of the attack nor the knife used was ever found. Nor did investigators find any physical evidence such as body fluids, hairs or clothing fibers to link Scott with the crime. The one Negroid hair that was found on the woman's clothing was not that of Scott's or his wife's.

But investigators noted that the victim's description of her attacker matched Scott and that the assailant clearly knew a good deal about her, including her address, her husband's name, job and the jargon used by military police. Scott lived in the same apartment complex as the woman, and because of his job as a criminal investigator in training would have had enough knowledge of police procedures to cover his tracks.

Investigators also discovered that Scott had borrowed a serrated steak knife from his apartment manager the day of the attack and never returned it. Scott said he used it to clean his stove and then threw it away unthinkingly. A forensic pathologist testified that at least one wound on the woman's neck was caused by a serrated knife.

The woman also provided a detailed description of Scott's car, and later picked it out of a parking lot as the one in which she had been abused.

Myers, one of Scott's attorneys, said yesterday, "I think {the jury} just came to the conclusion that it was a tossup -- and a tossup is not a guilty verdict."

Civil rights groups seized on the speed with which investigators focused on Scott as well as such deficiencies in the government case as the absence of physical proof, as evidence of racism in the prosecution of Scott.

How, they asked, could Scott have been singled out so quickly with so many blacks on the base? Noting that Scott's service record was unblemished and that his wife was expecting a baby, they further posed a question that proved difficult for the prosecution: What would Scott's motive have been for such a crime?

McNeil, the Marine prosecutor, said yesterday, "I saw and continue to see no evidence of racism in this case," and defended the government for going ahead with a second court-martial because, he said, the evidence warranted prosecution. "I have no regrets at all," he added.

The case became a crusade for a number of civil rights activists in Prince William County. Perhaps the most noteworthy was Lori Jackson, who assigned herself as a more-or-less full-time investigator for Scott's defense, starting a month before his first trial, and never gave up hope.

Jackson, who is suffering from a serious illness, could not be reached in her room at Washington Hospital Center yesterday. But she said through a hospital spokeswoman: "What pleases me most is that justice prevailed. And hopefully this will set a precedent for all servicemen."

Leino, the attorney for Scott who delivered an almost cathartic final argument on Wednesday, continued in the same vein yesterday. A burly former marine, he concluded the news conference with the words, "Lazarus, come forth!"

Lazarus is the biblical figure whom Jesus raised from the dead.