SGT. JAMES CAMPBELL OF THE Vanderbilt University Medical Center security force had just rounded the corner of Garland and 21st Streets in Nashville, Tenn., in his patrol car last Aug. 22 when he spotted a man exiting the parking garage wearing an ill-fitting wig and an Abraham Lincoln-style beard. "Something ain't right," the 21-year veteran radioed back to his office.

It wasn't. Campbell stopped and questioned the man, who was also wearing padding around his waist. He told Campbell that he had donned the disguise to spy on a girlfriend. A British West Indies driver's license identified him as Steven Maupin. The man allowed Campbell to search his nylon carry-bag, but the security guard's uneasiness only grew. Inside were additional disguises, a pair of latex gloves and, most troubling, a two-inch-in-diameter syringe containing a clear liquid and fitted with a four-inch needle. Campbell arrested the man for criminal trespass.

The suspicious visitor turned out to be not Steven Maupin—that name turned out to have been taken from a gravestone in Charlottesville, Va.—but Dr. Ray Mettetal Jr., a Harrisonburg, Va., neurologist who had studied at Vanderbilt's medical center in the 1980s. The liquid in the syringe was boric acid in salt water—which could be lethal if injected into the heart with the ice pick-like syringe.

What Campbell stumbled on that day has turned into one of the more bizarre tales in the annals of modern medicine. Police have charged Mettetal, 44, with the attempted murder of Dr. George Allen, head of Vanderbilt's department of neurosurgery, who in July successfully operated on Vice President Al Gore's mother, Pauline, after she suffered a stroke on the right side of the brain. "The motive is revenge," says Det. David Miller, chief investigator on the case. "Being a trained physician, [Mettetal] would know where to place a syringe so it could cause death."

Police say Mettetal, a handsome, soft-spoken man, harbored an intense grudge against Allen for more than 10 years after Allen refused to permit him to continue in Vanderbilt's neurosurgery program. Mettetal eventually became a neurologist—qualified to treat brain diseases, though not in the operating room. But what he really wanted to be was a neurosurgeon, considered among the elite of medical specialists. Mettetal came to believe that Allen had ruined his life, and he blamed Allen for his failure to be admitted to neurosurgery programs at a dozen other institutions to which he had applied.

In a Harrisonburg storage unit Mettetal rented, police found 29 bottles of toxic chemicals and books with such titles as The Complete How-to-Kill Book and Silent Death, a study of poisons and how to administer them. "We have a man, a brilliant mind, somehow gone awry," lamented Davidson County Judge William Faimon last Sept. 1, when he ordered Mettetal held without bond. The neurologist, who is charged with attempted first-degree murder and faces up to 25 years in prison, has pleaded not guilty. No trial date has been set.

Mettetal declined an interview, but his attorney, Patrick McNally, says the police case is built solely on circumstantial evidence. The boric acid in the syringe, McNally says, was ordinary contact-lens solution. The how-to-kill books, he points out, "can be purchased at any bookstore. They're not illegal." As to why Mettetal showed up at Vanderbilt in a disguise, carrying a veterinary syringe, McNally says, "We will present our explanation at trial."

Mettetal's arrest stunned many of his medical colleagues. "Anyone who knows him finds it difficult to believe," says Dr. John Jane, who worked with Mettetal at the University of Virginia. According to Dr. Frank Freemon, a neurologist who worked with Mettetal at Vanderbilt, Mettetal is a physician "of the best quality.... There are people who owe him their lives."

In fact, Mettetal showed great promise at the start of his medical career. The son of Ray Mettetal Sr., a respected retired general practitioner in Johnson City, Tenn., and his wife, Mattie, Mettetal played tennis at Science Hill High School and was a member of the Fellowship of Christian Athletes. After graduating from Hampden-Sydney College in Virginia, he attended medical school at the University of Tennessee. Mettetal graduated in 1976, married Linda Haile, then did general internships at hospitals in Mississippi and Tennessee. In 1981 he enrolled in Vanderbilt's neurology program.

There, Mettetal finally got his chance at neurosurgery. He was elated, his family recalls. He gave up tennis on weekends and in his spare time constructed cork models of the brain. But the euphoria was short-lived. In July 1984, Allen took over as chairman of neurosurgery from Dr. William Meacham, one of Mettetal's mentors. Only days later, Allen told Mettetal he was "not happy with his technical skills in the operating room," testified Allen at a preliminary hearing. Allen said he also expressed concern about Mettetal's "medical knowledge base." Allen told Mettetal they could work out a plan to address these concerns. "I didn't consider at the time that this was very negative at all," Allen said. Yet the next morning, Mettetal resigned. "I was shocked," said Allen.

About two weeks later, Mettetal asked to be reinstated. Allen refused. By then, he said, other doctors had told him that they, too, had reservations about Mettetal's work. On the surface, all seemed civil. "We never had a confrontation," said Allen, who never spoke to Mettetal again.

"Distraught" over the situation, his wife, Linda, testified in court in September, he returned to Vanderbilt's neurology department and completed his residency in 1987. In 1988 he entered a neurosurgery program at the University of Miami but returned to Nashville after three months. Officials at Miami won't comment on Mettetal's departure, and family members say he never discussed what happened. But Allen acknowledged that he may have played a role. When Florida's physician licensing agency contacted Allen about Mettetal, Allen testified that he expressed "some reservation" about his qualifications.

After that, her husband "was another person," Linda Mettetal told investigators. He expressed anger at Allen, she said, on "an ongoing basis"—at one point blaming the neurosurgeon even for the couple's inability to sell their Nashville home. But according to Linda, he never went so far as to threaten Allen's life. Her husband's growing bitterness took its toll on their 15-year marriage, and the couple, who have two children, divorced in 1991.

Mettetal left Nashville soon afterward for the University of Virginia. Although he could have earned $150,000 a year as a practicing neurologist, he accepted a fellowship for $20,000 a year. The trade-off? As a neurosurgical fellow, he was allowed to assist in brain surgery.

By last summer, Mettetal had moved on to Harrisonburg—and had begun acting strangely, his family told investigators. He kept a human brain in a jar on his mantle at home. At odd moments he would recite Bible verses aloud. He also began losing his temper over seemingly trivial matters. Police speculate that what may have pushed him over the edge was the publicity Allen received after treating Pauline Gore. When they searched Mettetal's storage space, they found notes on Allen's daily habits, photos of his house and his Vanderbilt locker.

In prison awaiting trial, Mettetal is reading classics, including Dickens's A Tale of Two Cities, according to Penny Hill, an emergency room nurse and friend from Lewisburg, Tenn., who visits him weekly. Hill reports that he is also studying the effects of prison life on the brain, as well as "why some people can't seem to function outside the penal system." Hill has never spoken to Mettetal about the charges against him. "He's the same Ray Mettetal I've always known," she says. "I can't see that he'd intentionally hurt anybody for any reason."