On a late-winter day about a year ago, someone — his identity and motive are still unknown — entered the home of William and Claire Hunter in Omaha. In his wake, two people were stabbed to death: the couple’s 11-year-old son, Thomas, and the family’s housekeeper, Shirlee Sherman, 57. Witnesses said they saw a young, well-dressed man carrying a briefcase or satchel enter and leave the residence around the time of the murders. The bodies were discovered by Thomas’ father, a physician and college professor, as is his wife.

Today, the police investigation drags on. Theories have been floated and abandoned. Nothing.

There was, however, this: On Jan. 21, 10 months after the killings, NBC’s Law & Order, the venerable cops-and-courts drama, aired an episode about a double homicide. The victims were a young boy and his family’s housekeeper, both stabbed to death in the boy’s home. Their bodies are discovered by the boy’s parents, both of whom are college professors. The chief suspect: a well-dressed man with a briefcase.

After watching the program later, William Hunter said he found it “eerily reminiscent.”

How would you feel if a traumatic personal event suddenly appeared as the plot of a prime-time entertainment program? During 19 seasons of Law & Order (and four spinoff series), a few hundred people have found out. One of TV’s longest-running and most honored programs, L&O uses real, “ripped-from-the- headlines” events — celebrity trials, political scandals, notorious crimes — as the basis for its crime-and- punishment plots. Although the stories tend to wander into make-believe, they rely on the lightly disguised depiction of real people and events for their immediacy and sense of authenticity.

The real people? They feel blindsided and used. No one in Hunter’s family saw the double-homicide episode, called “Pledge,” when it aired. Rob Hunter, the Hunters’ 23-year-old son, began getting the first calls about it from friends. “Did you see that?” they asked. “Did you know about this? Wasn’t it creepy?”

He didn’t. And it was.

“If the story was pure fiction,” Rob Hunter says, “it would be less sick.”

Joanne Banks, Shirlee Sherman’s mother and a fan of L&O, was so disturbed by a description of the program that she hasn’t watched it. She says flatly, “It’s not something I would want to see.”

William Hunter downloaded the episode from iTunes after friends mentioned it. He couldn’t finish watching. “It’s uncannily similar to what happened here,” says the elder Hunter, a pathologist who teaches at Creighton University. “It’s just very disturbing.”

The most disconcerting part, the family members say, is that no one from the network or the program contacted them. “My instant reaction was, how come we didn’t know about it?” says Rob Hunter, a Web designer in New York City. “How could they write something like that without talking to any of us? You see the warning that it’s all fiction. The fact is, it’s not all fiction.”

NBC won’t confirm that the program was based on the Hunter-Sherman deaths. Representatives of the network say the same thing in response to questions: All stories on L&O are fiction. The show carries this standard disclaimer: “The preceding story was fictional. No actual person or event was depicted.”

That’s more than just boilerplate. It’s a legal argument, with important implications for NBC and Wolf.

Since 2004, the network and the show’s creator have been fending off a lawsuit that claims there was just too much reality in one of the show’s dramatizations.

New York lawyer Ravi Batra says he was libeled by a November 2003 episode called “Floater” that revolved around a murder and judicial-bribery scandal. Batra claims that one of the villains of the story — a prominent, bald, Indian-American lawyer named Ravi Patel — was a barely camouflaged version of himself. Batra is an Indian-American lawyer prominent in New York City legal circles. He’s also bald.

Batra’s name was in the New York press several months before the “Floater” episode aired; he was linked to a bribery scandal in Brooklyn involving another lawyer and a judge. Batra was never charged in the case, which, unlike the TV program, did not include an act of violence.

With a little spicing up, Batra’s lawsuit against L&O might itself make a compelling episode in the series. The suit, seeking $15 million in damages, turns on the legal principle of “libel in fiction,” the idea that a fictionalized depiction can damage a real person’s reputation. Batra said he was harmed because the name, ethnicity and appearance of the character are so similar to his.

Although libel-in-fiction claims rarely succeed, a New York State Supreme Court judge shot down a defense motion last year to dismiss Batra’s suit, clearing it for trial. There was “a reasonable likelihood that the ordinary viewer, unacquainted with Batra personally, could understand Patel’s corruption to be the truth about Batra,” Justice Marilyn Shafer wrote. The matter is still awaiting trial.