WWW- A nearly four-month-old Internet drama in which the cryptic video musings of a fresh-faced teenager became the obsession of millions of devotees – themselves divided over the very authenticity of the videos, or who was behind them or why – appears to be in its final act.

The woman who plays Lonelygirl15 on the video-sharing site YouTube.com has been identified as Jessica Rose, a 20-ish resident of New Zealand and Los Angeles and a graduate of the New York Film Academy. And the whole project appears to be the early serialized version of what eventually will become a movie.

Matt Foremski, the 18-year-old son of Tom Foremski, a reporter for the blog Silicon Valley Watcher, was the first to disinter a trove of photographs of the familiar-looking actress, who portrayed the character named Bree in the videos. The episodes suggested Bree was the home-schooled daughter of strictly religious parents who was able to find the time to upload video blogs of her innermost thoughts.

The discovery and the swift and subsequent revelation of other details surrounding the perpetrators of the videos and the fake fan site that accompanied it are bringing to an end one of the Internet’s more elaborately constructed mysteries. The fans’ disbelief in Lonelygirl15 was not willingly suspended, but rather teased and toyed with. Whether they will embrace the project as a new narrative form, condemn it or simply walk away remains to be seen.

The masterminds of the Lonelygirl15 videos are Ramesh Flinders, a screenwriter and filmmaker from Marin County, Calif., and Miles Beckett, a doctor turned filmmaker. The high quality of the videos caused many users to suspect a script and production crew, but Bree’s bedroom scenes were shot in Mr. Flinders’s home, in his actual bedroom, typically using nothing more than a Logitech QuickCam, a Web camera that retails for about $150.

Together with Grant Steinfeld, a software engineer in San Francisco, Mr. Flinders contrived to produce and distribute the videos to pique maximum curiosity about them.

The photographs of the actress, which made it clear that Ms. Rose has been playing Bree in the videos, were cached on Google.

“We were all under N.D.A.’s” Mr. Steinfeld said, referring to non-disclosure agreements the cast – and their friends – were asked to sign to preserve the mystery of Lonelygirl15. “They had a lawyer involved,” he said. “My first impression was like, wow, can this be legitimate? Is this ethical? I was very concerned about that in the beginning.”

But after he came to understand the project, Mr. Steinfeld said, he came to believe that something truly novel was at hand. “They were like the new Marshall McLuhan.”

Mr. Flinders and Mr. Beckett obscured their location by sending e-mail messages as Bree from various Internet computer addresses, including the address of Creative Artists Agency, the Beverly Hills talent agency where the team is now represented. Amanda Solomon Goodfried, an assistant at the agency, is believed to have helped Mr. Flinders and Mr. Beckett conceal their identities. Moreover, Ms. Goodfried’s father-in-law, Kenneth Goodfried, a lawyer in Encino, filed to trademark “Lonelygirl15” in August.

The story of how Mr. Flinders, Mr. Beckett and Ms. Rose were discovered in spite of their efforts to hide, and prolong the mystery, sheds light on the nature of online wiki-style investigations and manhunts. When Mr. Steinfeld’s dummy site, which had been set up before the first Lonelygirl15 video was even posted, struck users as suspicious and unsupervised – Mr. Steinfeld says he grew tired of running it, and dropped out of the project – fans set up their own site devoted to Lonelygirl15, which soon attracted more than a thousand members.

Both sites drew contributions from novelists, journalists, academics, day traders, lawyers, bloggers, filmmakers, video game designers, students, housewives, bored youngsters and experts on religion and botany. In the cacophony of conjecture, analysis, close-readings, jokes, insults, and distractions, good information sometimes surfaced.

Last month, a Lonelygirl15 fan discovered and posted a trademark application by Mr. Goodfried, which seemed to prove that the videos, which presented themselves as nothing but a video diary, were at least in part a commercial venture. Then, last week, three tech-savvy fans, working together, set up a sting on the e-mail being used by “Bree”; the operation revealed to them the I.P. address of Creative Artists Agency.

On the strength of this information, Mr. Foremski was confident he could find some trace of Bree on the Internet. He was sure that any participant in a semiprofessional production like Lonelygirl15 would have posted pictures somewhere. Sure enough, they had.

Mr. Steinfeld, on learning that Mr. Flinders and Mr. Beckett had been found out, offered his photographs of Ms. Rose as proof of his involvement in the Lonelygirl15 videos. He had been hired to take the pictures on the set at the start of shooting.

The series, which Mr. Flinders and Mr. Beckett plan to continue on a site overseen by them, may play differently with fans now that they know for sure that Bree is an actress. Part of the appeal of the series was that the serious-minded, literate Bree offered an unbeatable fantasy: a beautiful girl who techy guys had something in common with.

On learning that Ms. Rose was an actress whose interests, unlike the scientific and religious issues that fascinated Bree, ran to parties and posing, one fan wrote, “Very cute, but she’s really not into Feynmann and Jared Diamond! (I’m heart-broken …But a wonderful actress, had me fooled into thinking she was a geek like me.)”