RICHMOND, Va. — The forensic scientist cut off the tip of a cotton swab and taped it to a lab sheet next to a snippet of stained clothing.
Always save a piece of what you test, Mary Jane Burton instructed her watchful trainee.
But why? This was 1977, years before the invention of DNA testing. Yet day after day, she repeated this seemingly pointless procedure under the glow of the cramped laboratory's fluorescent lights -- taping swabs smeared with blood or semen or saliva and inserting them into their case files.
Years later, when the ache of arthritis in her hands grew unbearable, she retired from the Virginia state crime lab, leaving behind scores of forgotten files, each holding samples imprinted with nature's barcode.
The lab she worked in is gone now, but a few miles away, behind a secure, rolling metal door in a museum-like beige building, is a cavernous warehouse where 17 numbered rows of metal shelves tower 28 feet to the ceiling. They hold 75,000 covered cardboard boxes -- more than 4,000 of them the property of the Virginia Department of Forensic Science.
Many of the tiny pieces of bloodied clothing and cotton swabs that Burton taped down were tucked inside their manila folders, filed away in boxes scattered throughout the room.
There they remained undisturbed for years, waiting for science to catch up with them -- and waiting for someone to discover that they were there.
The bicyclist sat on the side of the tree-lined path, clutching his knee.
He must be injured, a young woman thought when she saw him. She set down the bucket of chicken she'd been carrying home for a late dinner and walked over to help.
The man grabbed her, dragging her off the path into a wooded area. He told her he had a gun and demanded money. She handed him all she had -- 21 cents. He snatched her wallet and found another quarter. Then he punched her in the face.
For three hours, the woman was raped, sodomized and beaten. The rapist, who was black, told his victim that she reminded him of his white girlfriend.
At the same time, in another part of town, a young black man named Marvin Anderson stood in his mother's driveway, washing his orange Oldsmobile. Back at their apartment, Anderson's young white girlfriend was preparing dinner.
It was July 17, 1982, and interracial relationships were rare in the small Southern town.
It wasn't long before Anderson was under arrest.
Burton handled the evidence in the young woman's rape case just like all the others. When she finished testing the specimen on a cotton swab, she cut off the top, took a strip of Scotch tape and secured it to a lab sheet.
At the defense table, Anderson was terrified. How could anyone think he had done such horrible things?
Burton took the witness stand. She detailed for the jury the evidence she had received and tested -- vaginal and oral swabs, hair cuttings, fingernail scrapings.
The victim was a type AB secretor, which complicated matters, she explained. The assailant's fluids were mixed up with the victim's, and her AB blood type essentially masked his blood type.
"So because of the victim's blood type, it's impossible to say what the type was of the person that assaulted her?" Ramon Chalkley, the assistant Commonwealth's attorney, asked Burton.
"That's right," she replied. She could draw no other conclusions from the physical evidence.
But the victim testified that the man who had brutalized her -- a monster, she said, who had the eyes of the devil -- was definitely Anderson.
"His face will always haunt me," she said.
Other witnesses insisted that Anderson had been washing his car at the time of the attack. His attorney pleaded with the jury: "Two wrongs will never make a right."
The pleas were no match for the prosecutor's gruesome description of the assault.
"It's the stuff nightmares are made out of," Chalkley said. "The things that make you wake up in the middle of the night in a cold sweat and each second seems like an eternity, because you're frightened to move."
The jury foreman read the verdict and Anderson's world went dark.
His sentence: 210 years in prison.
He could hear anguished wails as his mother fell apart in the courtroom. He turned to look at her but saw nothing but darkness. His body was going numb.
He was a regular 18-year-old kid -- a volunteer firefighter, active in church, close to his family. How was he going to survive prison? How did he end up here?
Why wouldn't anyone believe him?
Standard procedure in Virginia was for biological evidence to be returned to the authorities after testing. After a few years, it would be destroyed, except in death penalty cases.
Why Mary Jane Burton insisted on saving such samples is as big a mystery as Burton herself.