When 19-year-old Kaycee Swenson died of cancer last week, hundreds, perhaps thousands, grieved.

     And why not. Kaycee had lost the battle against leukemia.

     But what set this young lady's death apart from the thousands who die from the disease each year is that young Kaycee fought for her life publicly, seeking out an Internet community to bare her soul during the agonizing battle.

     Kaycee was astonishingly open, remarkably candid. She elucidated her fears in the starkest terms and told of long, "traumatic" stays in the hospital. She autographed a hat and mailed it to one admirer.

     Kaycee's Web fans became her friends. They called her, they forwarded hundreds of e-mails to her, sent countless get-well cards. One individual even set up a Web site in her name.

     Kaycee was a fake.

     Brewed from the imagination of Debbie Swenson of Peabody, this cancer victim never existed and her public, yearlong story was pure fabrication.

     "I am a moral person," Swenson, 40, said Monday from her home. "I lived with it every day, and felt guilty every day. It's been a nightmare for the past week. I didn't know the reactions would be so strong."

     Swenson, a married mother of two who describes herself as "a computer idiot," claims that she alone was the author of the separate mother-and-daughter weblogs about Kaycee but that she never set out to hurt or deceive anyone.

     Swenson claims Kaycee was a composite character, a "friend of a friend" who Swenson says died of leukemia years ago.

     She also admitted to opening a post office box in Newton but said her intention was not to cash in on people's sympathy by luring mailed gifts.

     "It was not intended to hurt anyone or to get money," she said.

     But for almost a year she is guilty of having intentionally woven many people into the life of a person struggling against the ultimate odds.

     That alone is not a crime.

     Online communities do not come with factual warranties, guarantees that guard against even the most salacious information. Users log on at their own risk.

     But this story was powerful -- the revelation that it was a hoax even more so -- and for a week the Internet has been rife with stories on Kaycee's fake death.

     Nationally known technology writer Dan Gillmor posted a news story on SiliconValley.com, published by the San Jose Mercury News, asking "Was Kaycee real?" and pointing up how a skeptical Indiana woman uncovered the ruse.

     Two days later, Internet Content West ran its own blurb.

     "The story is confusing but what appears to be true is that a weblog portraying Kaycee's story was a hoax," noted online columnist Steve Outing wrote.

     She even fooled the New York Times. Last August, staff writer Lisa Guernsey used "Kaycee Swenson, a high school senior in Wichita, Kas.," as a source in a technology story about Internet- wired college dormitories.

     Guernsey wrote: "But she said she also hung out with friends in the physical world, listening to music and playing basketball. 'You have to balance it,' she said."

     Guernsey reported that Kaycee would enroll full time at the University of California at San Diego.

     The hoax began unraveling last week as fascinated readers of the mother-and-daughter online diaries, all written by Swenson, began noticing irregularities in the tales and making calls to check up on the stories.

     At the forefront of a cadre of Internet writers who began poking holes in Swenson's story was Saundra Mitchell, a freelance writer and aspiring crime-story screenwriter from Indiana. Mitchell, 27, is herself a veteran online diarist, writing about her own experiences with the disease hyperprolactinemia, a tumor disorder of the pituitary gland.

     "I learned about Kaycee only a few weeks ago," Mitchell said Monday. "Then, suddenly, she 'died.'

     "I tried to check for her obituary, but the more I checked, the less I found. At first I was concerned. Then I started to get mad. It was my chance to play detective."

     And detective she became. Working with former journalists and Internet experts nationwide, she began piecing together who Kaycee might be.

     Experts traced Kaycee's online postings to Swenson's Internet account. Others tracked down the source of a supposed photo of Kaycee, which turned out to be the picture of a college basketball player at Southern Nazarene University in Bethany, Okla.

     The investigators have even formed their own online site devoted exclusively to debunking the Kaycee myth: http://groups.yahoo.com/group/kaycee-nicole.

     Mitchell said she called the Newton Kansan, Kaycee's alleged hometown newspaper, and asked for a report of recent obituaries, but that paper's managing editor said he had no such report and that he would have remembered such a stirring story crossing his desk.

     Over the weekend, Peabody police, newspaper office, real estate agents and others received calls from various gumshoes, all seeking to check details of Kaycee after electronic traces of her postings pointed to Peabody, not Newton.

     On Tuesday, Peabody Police Chief Jeff Pohlman confirmed that the matter was "under investigation."

     A representative of the Wichita branch office of the Federal Bureau of Investigation could not comment on the case because charges or complaints filed with that federal agency are not public information until arrests are made.