Lois Duncan knows what they did this fall.
Filmmakers took her book, "I Know What You Did Last Summer," something of a classic in the young adult suspense field that she helped to create in the early 1970s, and made it into one of the season's biggest hits.
The movie, though, eviscerates the plot of her 1973 morality tale as thoroughly as its hooded stalker slices and dices photogenic teen-agers. The changes are especially troubling to Duncan, whose own teen-age daughter was killed eight years ago in a shooting that remains unsolved.
For their part, the filmmakers were unaware of the gruesome real-life link and knew nothing of it until contacted by The Sun, according to John Jacobs, president of worldwide marketing for Mandalay Entertainment.
But Duncan, 63, is still upset. She first went public with her displeasure with the film via the Internet, although she has backed off from some of her stronger statements to avoid potential legal problems. "It's not just like I'm real picky. This [film] simply made statements that were upsetting to me, by trivializing violence and making murder seem like a game, which was not true to the spirit of my book," Duncan says by telephone from her North Carolina home.
"But let me be clear," she adds cautiously. "They had the absolute legal right to do this."
The teen-agers in Duncan's book hit and kill a young boy on his bike, only to be pursued by an ingenious avenger in a story tricked out with several twists but no slayings.
The connection between the accidental death and the gory retribution in the film is more tenuous, with greater emphasis on the method of dispatch than the motivation.
The screenplay for "I Know What You Did" was written by Kevin Williamson, best known for the surprise hit "Scream." But most critics have found "I Know" to be little more than a well-cast stereotype of the kind of movie that "Scream" sent up so wittily.
As for the parallels to Duncan's own tragedy, Jacobs of Mandalay Entertainment said: "It's a sad story and I think it would be inhuman and insensitive not to have some compassion for that. The truth is, it was not a fact that was well-known to anyone involved in the movie-making process."
While she is displeased with the film, Duncan has decided she can use its high profile to draw new attention to her daughter's case, which she believes was a contract hit.
The shooting -- a closed case, as far as Albuquerque, N.M., police are concerned -- occurred July 16, 1989.
Duncan's daughter Kait Arquette, 18, who had told her family that she was breaking up with live-in boyfriend Dung Ngoc Nguyen, was shot while driving her car. Her family believes she was killed because of her inadvertent knowledge of organized criminal activity and continues to seek any leads they can find.
Duncan wrote a book about Kait's death, 1992's "Who Killed My Daughter?" and used her subsequent book tours to generate publicity about the case.
Now she has decided to use the popularity of "I Know What You Did" to direct people to her Internet site (http: //www.iag.net/barq/kait.html), where the known details of the shooting are laid out in great detail. A private investigator continues to work on the case in Albuquerque, and an article is expected in a forthcoming issue of People.
Duncan has been writing and publishing stories since she was 13. The author of more than 45 books, she says she has come to believe in the paranormal experiences she once used merely as plot points.
She is especially haunted by the eerie similarity between Kait's death and the plot of a book she had just completed at the time, in which a young woman is pursued by a hit man in a Camaro.
As for "I Know What You Did," she hopes new readers will find the book as a result of the movie, which was at No. 1 for three weeks and remained in the top 10 over the weekend.
It has earned $60 million to date.
"I hope that will save my reputation," she says, although her name has not been used to promote the film.
"They seem to have hit upon something that is making them a great deal of money, which says something about I don't know what it says. Something I'd rather not know."
Pub Date: 11/19/97