Her murder in 1995 was the type of case that haunted even a seasoned homicide investigator like him: Just 16 years old, Sanchez had been sexually assaulted and strangled, the noose cinched with a toothbrush.
Even worse, in the three years before, two other young Hispanic females on the north side of town had been similarly assaulted and strangled. The second was only nine years old.
The killings haunted investigators. "The innocence of those girls, and knowing we were dealing with a sexual predator -- it's just different," says Billingsley, a Harris County sheriff's lieutenant. "Every day I'd think about those girls. Every day it was on my brain."
Sanchez had disappeared almost 11 months after the nine-year-old's murder. A week passed before a man called KPRC-TV with directions to the field where her body lay.
Then he added something that police had suspected but had hoped wasn't true:
A serial killer is on the loose.
Police were convinced that the anonymous tipster was the killer himself: hungry for attention, eager to display his handiwork, daring them to catch him.
The cops and deputies formed a task force, desperate to stop him. Only when leads fizzled and the killer failed to strike did the task force disband and its detectives take on other cases.
But they never really moved on. Billingsley thought about the killer every time he went to the post office on West Cavalcade -- Sanchez had lived just across the street. Or whenever he saw a van that matched the one spotted at the crime scene.
Sometimes they'd talk about him, Billingsley says. Why had he thrust himself into the limelight, and then stopped? "Did he die?" "Is he in prison for something for else?" "Has he moved away?"
Only after they caught him did they realize it was none of the three. In the eight years after Sanchez's death, he'd gotten married and divorced, fallen in love again and started a business.
Anthony "Tony" Shore had crossed paths with law enforcement numerous times. He'd been in a squad car at least once, in criminal court and at the police station. But no one ever really noticed the friendly dark-haired guy with the pierced chin.
And that's how it had always been for Shore. Even as a child, he seemed driven by two impulses: to seek attention and to molest females. He went from grabbing and groping to killing. He cruised high schools. Molested his own daughters. Tried to pick up a hooker. Then, after a few murders, he called the TV station to give police an added push.
Everyone who might have stopped him, from relatives to social workers to prosecutors, seemed to be looking the other way. Even the people who detected his odd behavior failed to put the pieces together. And as Houston police detectives worked tirelessly to catch the killer, their own DNA lab failed to test the evidence that could connect Shore to the crimes.
In the end, it was left to science to nab him. When Shore confessed last fall, it was to more crimes than investigators had suspected: the murders of four women, the violent rape of a fifth. But by then, it was too late.
When it comes to serial killers, Tony Shore is more Ted Bundy than Jeffrey Dahmer. His hairline has started to recede, but he is still good-looking, with dark puppy-dog eyes and a neat goatee. He has long been fastidious; even as a child, he hated to get dirty. His sisters used to tease him for folding his socks over a hanger, for insisting on silk underwear, for instructing them on the importance of eating their sandwiches in a straight line, teeth marks precise as a row of type.
Shore was born in South Dakota. His father, Rob, was stationed at an air force base there; his mother, Deanna, had been honorably discharged after getting pregnant with Tony.
After Rob's discharge, the Shores relocated to California -- the first of nine moves the family would make before Tony started high school, crisscrossing from California to Florida, then finally landing in Houston. "When I'd get a better job offer, I'd move," Rob Shore says. Since he was "in computers before there were computers," as he puts it, there was no shortage of offers.
Tony was well behaved and hypercompetitive, his mother says; he always had to be the best. His family marveled at his ability to play any instrument, from piano to trombone to guitar. He won mention in the Sacramento Bee for his recital of a Bach musette when he was just five years old.