A little boy and his dog discovered victim No. 32 when they were out for a walk in some marshy woods several weeks ago. The dog came up with a bone, and then the boy saw a skull. Nearby, the police later would find earrings, shreds of clothing and a belt tied around a tree. Investigators believe the killer used it to bind the young woman while she was sexually assaulted.

Still unidentified, the 32nd victim was added to a grisly FBI database that chronicles nearly three decades of unsolved abductions, disappearances and murders. The crimes have two factors in common: gender and geography. All the victims were female, and almost all the crimes occurred a few miles on either side of Interstate 45 along the 50-mile stretch between Houston and Galveston, an area of refinery towns and suburban developments interspersed with bayous, forests and cattle ranches.

Nowhere else in the country are police so bedeviled by so many unusual crimes occurring within such a well-defined area. Now, for the first time since the first victim's corpse was discovered in 1971, investigators believe they are making progress both in breaking individual cases and devising a method to attack the overall problem. But early indications are not good for those who hoped it could be brought to an end by finding one serial killer who could be captured and put behind bars.

"It appears that there may be multiple serial killers," said Don K. Clark, special agent in charge of the FBI's Houston division.

If that suspicion proves true--and investigators caution that they remain far from bringing charges in these crimes--then the bizarre pattern of killings along I-45 would be the result of an equally bizarre occurrence. Police now worry that for nearly three decades this stretch of coastal plain has served as a hunting ground for any number of murderers who share a deadly obsession. Over time, it appears to police, the killers have come and gone but shared in common the site they selected to find their victims--or to dump the bodies of people killed elsewhere.

In fact, the bayous lined with longleaf pine, beech and live oaks appear to have served as a dumping ground not only for local killers but also for Houston's predators. The refineries and ports draw transients. The small towns and country roads have proved easy places to hunt victims. The patchwork of jurisdictions makes it easy to cloak activities simply by crossing the city limits.

The victims in the I-45 cases typically disappeared while out alone, only to be found dead and abused in a remote spot weeks or months later, leaving no hint as to their attacker's identity or motive.

The investigation took an important turn after several particularly horrific and well-publicized crimes in 1997. First, Laura Smither, 12, disappeared while jogging near her home, and then Jessica Lee Cain, 17, vanished, leaving behind only her empty pickup truck parked on the shoulder of I-45. Smither's decapitated body was found in a pond almost three weeks after her disappearance. Cain is still missing.

The initial search for these two girls, when they were presumed alive, brought together more than a dozen local and state police agencies along with the FBI. These various law enforcement organizations have continued to pool their resources under an FBI initiative.

"Before Laura Smither and Jessica Cain, each one of us was in his own little world, investigating our own individual cases, and we would have no way of knowing that some fellow we wanted to question in one murder, and had been a top suspect, had already been questioned in a very similar murder just a few miles down the highway," said Lt. Tommy Hansen of the Galveston County Sheriff's Department.

Aside from lack of coordination, the investigations suffered from a lack of resources in the small-town police departments. "Until recently, we didn't even have a Polaroid for crime scene photographs," said Sgt. Brian T. Goetschius of the Texas City police. His department has only six detectives. The Cain disappearance has produced 2,332 leads in two years.

Some evidence pointed to a serial killer long ago. Two girls disappeared from the same convenience store in the 1970s. Four bodies were found between 1984 and 1991 in a scrubby patch of pastures dubbed the "killing fields." More subtle patterns now are emerging from a computer analysis of the evidence. The victims seem to cluster according to physical type, such that it appears one killer has a preference for short, slim, brown-haired women. Another killer seems to have demonstrated distinctive habits in the way he disposes of bodies, investigators said.

Stark similarities in several early cases suggest that a serial killer was active in the area in the 1970s, but it is unlikely he will ever be identified because so much time has passed. Further complicating matters, one of the most infamous criminals in Texas, Henry Lee Lucas, who is in prison on convictions in nine killings, roamed the Gulf Coast when some of the early I-45 murders took place, but he has not been linked definitively to any of the unsolved cases.

Investigators got lucky in the Smither case when they cross-referenced the names of known sex offenders living in the Houston area against the names of workers at a construction site near the Smithers' home who had been let off work close to the time of her abduction. The computer spit out the name of William Reece, then a 37-year-old bulldozer operator who had served time in Oklahoma on a rape conviction.

A search of his home and vehicles failed to produce conclusive evidence against him, and Smither's body was so badly decomposed that it did not yield the kind of DNA evidence often used to identify perpetrators in sexual assaults. Then even as the police were trying to build a case against him, Reece was arrested for a botched abduction in which his intended victim managed to escape and testify against him.

Reece faces a 60-year prison sentence for the crime and has been publicly identified as the prime suspect in the Smither murder. In scrutinizing Reece's recent life, investigators said they have developed leads potentially linking him to one and perhaps two other unsolved disappearances.

Police also are closely following another suspect who remains at large on the I-45 corridor, but who never has been publicly identified.

"We know a guy, we know him very well, a guy who has killed before and who had some kind of contact with five of the girls, but all the evidence is circumstantial," said police Lt. Gary D. Ratliff of League City, a town of 50,000 where the "killing fields" are located.

"What do you do when there are no witnesses and you recover a victim, weeks or months after the crime, and the physical evidence is all gone?" Ratliff said. "What do you say to the parents when all you have to go on are bones that critters have been at?"

The unnamed suspect suffered physical injuries in an automobile accident a few years ago and appears to have gone "dormant" since then, Ratliff said. While that is good news in one sense, his lack of activity makes it less likely he might commit a mistake that would allow him to be caught.

Investigators who have lived with the unsolved cases for years at a time do not bother to hide their frustration at not being able to solve the crimes or their feeling that they don't have enough resources to do the job. "There is no more than a handful of detectives in any of our departments and we have to handle everything else that comes in even while we are trying to work on these cold cases," Hansen said.

Although it cannot address the staffing limits on the small local police departments most responsible for solving the murders, the FBI is providing technology, expertise and now a new tactic.

With an Internet posting and other efforts, the FBI this month is attempting to publicize six recent abductions, crimes that fall under the federal kidnapping statute. It is the same tactic successfully used in the Unabomber investigation when the publication of the "manifesto" prompted the family of Theodore J. Kaczynski to turn him in.

"We want to attract public attention to these crimes because we believe there is someone out there who knows something, someone who might have overheard something, who might have seen something, someone who might be close to one of the killers and might now be willing to come forward," Clark said.

Killing Corridor In East Texas

More than 30 unsolved disappearances and killings have occurred near a stretch of Texas highway over the past three decades. Several are being investigated as serial murders.

1. "Jane Doe":

The body of a short, small-framed white woman, with light brown hair, likely between 23 and 26 years old, was found on Feb. 2, 1986, in a field in League City, where the bodies of three other victims have been discovered.

2. "Janet Doe": The skeletal remains of the victim were found in a League City field on Sept. 8, 1991. She is believed to be similar in stature and age to "Jane."

3. Laura Smither: The 12-year-old's decapitated body was found on April 3, 1997, in a pond in Pasadena.

4. Jessica Lee Cain: The 17-year-old disappeared on Aug. 17, 1997. Her pickup truck was found on the shoulder of Interstate 45 in La Marque. Cain is still missing.