As she lay dying, in 1995, Geneva Thompson, 96, turned to her daughter Collene Campbell with a dramatic request. Seven years earlier Thompson's son Mickey, a legendary drag racer and speed record-holder, had been shot dead in front of his home. No one had ever been charged. "Honey, I want you to take off my necklace and put it on," the frail widow said, indicating a diamond-heart pendant that had been a gift from her late husband. "Put it on and wear it until they get the man who killed my son and your brother."

On Nov. 6 Campbell, now 74, walked into a courtroom in Pasadena, Calif., wearing the necklace. At the defense table sat businessman Michael Goodwin, 61, who is charged with ordering the murder of Mickey Thompson and his wife, Trudy. That there even is a trial after so many years is the result of dogged police work, not to mention the persistence of Campbell, who put up a $1 million reward and badgered cops to keep the case alive. Indeed, Goodwin himself accuses Campbell, the former mayor of San Juan Capistrano, of ruthlessly using her clout to have him railroaded. Says Goodwin: "I know I'm only being charged because of Collene Campbell's political juice."

As prosecutors tell it, the murder of Thompson was the result of a business relationship gone sour. Thompson had had an impressive career as a professional driver, pushing his Challenger I car to more than 400 mph on the Bonneville Salt Flats in 1960—one of hundreds of records that he set—and earning the label "The Fastest Man on Earth." He also held dozens of patents. In 1984 Thompson went into business with Goodwin, a concert and sports promoter who invented the motorcycle sport of Supercross.

Thompson quickly accused Goodwin of cheating him and began a series of lawsuits. In 1986 Thompson won a judgment of more than $500,000 against his ex-partner. With all the animosity, Thompson feared Goodwin would try to kill him and Trudy, according to Campbell. "Mickey said, 'I'm afraid Goodwin's gonna hurt my [Trudy],'" Campbell recalls. "'He's capable of it—I feel it in my bones.'"

On March 16, 1988, two men in their 20s wearing hooded jogging suits attacked Mickey and Trudy in Bradbury, Calif., as they left for work. Neighbors heard Mickey plead, "Don't hurt my wife." The gunmen shot Mickey seven times, Trudy twice, and escaped. The shooters were never caught or identified. As Campbell vowed to the Los Angeles Times, "They got one more Thompson to take out if they think they're going to walk."

Police had suspicions—Campbell had told them about Goodwin—but no evidence. Still, Campbell pestered the police to keep digging and made sure the case continued to get media coverage. She also steered them to potential witnesses. "If we look through our pain and tears," says Campbell, who put up the $1 million reward (which has yet to be paid) with the help of her husband, Gary, a businessman, "we can see opportunity." (One police memo from the time refers to Campbell as a "pain in the ass.")

The current lead detective, Mark Lillienfeld, says that in the mid-'90s investigators took a fresh look at the murder and had it featured on America's Most Wanted. "That generated some good leads," he says. Among other things, a witness has said that he saw someone who resembled Goodwin with a pair of binoculars in the vicinity of the Thompson home in the week before the killing. Another witness, a former associate of Goodwin's, said the accused had said, "I am going to kill that son of a bitch." (In a jailhouse interview with PEOPLE, Goodwin insisted that his statements have been misinterpreted. "A lot of things were said during the litigation in the heat of the moment," he says. "These were not threats.")

Meanwhile, Campbell says she feels that her lost loved ones are in court with her. "I feel them all the time," she says. "They're all looking down and saying, 'Hey, hang in there, you're doing what's right.'" Regardless of the verdict, she says, she'll wear the necklace until she dies. "It's kind of stuck to me now," she says. "It represents a lot of love and toil."