From PEOPLE Magazine Click to enlarge
All his life, Bobby Neighbors had been haunted by his mother's murder. There were the whispers in the tiny town of Pawhuska, Okla., about how she died, the teasing from other kids about not having a mom. As he grew older he visited her grave whenever he could. "I'd let her know what was going on in my life," says Bobby, who was just 7 months old when she died. "It made me feel better." Then in February, after talking with a friend about how much he wanted to solve her murder, the high school sophomore came to a decision. He jumped on his bike, rode to Joannie Goodwin's grave and delivered a promise: "I'm going to find out who did this to you."

Within days Bobby, 15, had started up a Facebook page in his mother's name. His first posting was a letter to her killer. "I am not looking for a fight. I am not looking for revenge," he wrote. "I am not looking to hate you. All I am looking for is the truth." He also met with Osage County Sheriff Ty Koch, grilling him on the delays and details of the case. "I had a lot of questions, like why hasn't this case already been closed," says Bobby, whose cherubic face and Justin Bieber bangs belie his fierce determination. Aided by local TV and newspaper coverage of the site, tips began pouring in, including bona fide leads investigators say they are pursuing. While the sheriff will not elaborate on what those leads are, he did confirm Bobby's tips point to the same suspects cops have been interested in for years. Earlier this year Koch had the Oklahoma State Bureau of Investigation send DNA samples to the FBI's crime lab for more complex testing. He's still waiting for the results. (The FBI would not comment.) "It'll either blow this thing out of the water," Koch says, "or we'll be back to the drawing board."

Joannie Goodwin was an 18-year-old single mother when she vanished on Sept. 22, 1996, reportedly while walking home after a friend's truck broke down. A week later two fishermen found her body floating in Bird Creek, a mile northwest of Pawhuska. She'd been shot to death, wrapped with electrical wire and weighted down with a large brick. Investigators were stumped. "There really wasn't a motive," Koch says. "That's what's been so frustrating." Heartbroken over her daughter's death, LaVern Neighbors focused her attention on raising her grandson, going it alone after her husband, Todd, died in 2003 while undergoing a heart transplant. "Bobby's all that's kept me from really losing it totally," says LaVern, 60, who works at a local senior citizens' center. "I had nightmares. I could hear her screaming."

As the years passed, cops made little headway in Joannie's case, despite interviewing more than 40 people. A couple of years ago, a new investigator took a fresh look at the file and identified possible suspects whom cops had overlooked before. "We did a couple of searches and tracked down some vehicles we knew people had back then," says Koch, who was on the force when Joannie died but was not in charge of the investigation. "We got some forensic evidence. We're currently waiting for lab results on that."

Bobby doesn't remember how he first learned about his mother's murder; he says he just grew up knowing about it. "My grandparents never tried to hide it from me or lie to me about it," he says. (He did track down his father a few years ago, but the two have no real relationship.) Sometimes, he says, he imagines what it would have been like to be raised by his mom, whose pictures are still on walls throughout the modest wood-frame house he shares with his grandmother. "I wonder if I'd live around here, if I'd be who I am today," he says. "But really, I don't know how different it would have been." His girlfriend Madison Ervin, 15, recalls Bobby telling her about his mother's murder when they were in fifth grade, but most folks in town already knew. Christina Finn, one of Joannie's best friends, says the reason Bobby goes to a school in another town is because local kids would tease him. "They'd say, 'At least I have a mom, at least my mom wasn't found in the creek,'" she says.

And always, he wondered who could have done such a horrific thing to her-and why. At Bobby's first meeting with the sheriff, after his Facebook page had gone up, Koch laid down some ground rules. "I said, 'You've got to be careful about what you type on there. You don't want to plant information. Just be careful,'" Koch says. The two now meet regularly. Each time, Bobby comes prepared with a list. "I think of objectives, stuff I'd like to accomplish," he says, "like, call the FBI to find out what's taking so long with the DNA. Bring in so-and-so for a lie-detector test. Stop passing the buck." Koch takes the teenager's gumption in stride. "He's a real bright young man," says Koch. "He wants to find out what happened, and that's good."

As for LaVern, she's not surprised her grandson-a regular teenager with tons of friends, who runs track as well as logging hours scouring the Internet for clues-believes he can help solve his mother's murder. "I knew when he got to a certain age he was going to do this," she says, "because that's Bobby." Now that he's officially started this crusade, don't expect Bobby to give up anytime soon. "I don't care if I'm 20 and have to go get a degree so I can investigate this on my own," he says. "I will do it."