'No matter where I go, what I do, I'm always thinking of her.'

Since their 15-year-old daughter went missing more than three agonizing months ago, Wes and Cindy Wiese of Buxton, Maine, have left the lights on: pillar candles on the kitchen countertop burn all day, and multi colored Christmas lights on a Norway spruce in the front yard blaze all night. It's a ritual that keeps their hope from disappearing, too.

"Every morning, you wake up you say, 'God, I hope today's the day I get a phone call saying Coreen's been found and she's in Florida, on a beach, tanning herself,' " says Wes Wiese, 49. "But every night you go to bed," he starts, but cannot finish his sentence. He dabs his eyes with a wad of cocktail napkins. "You don't know if she's had a good meal," he adds. "You don't know if she's warm."

Coreen Faye Wiese mysteriously vanished near Buxton, a rural town of 7,434 about 20 miles west of Portland, on Nov. 8. Authorities are investigating several possible scenarios: that she killed herself, ran away, or was kidnapped by a stranger. They have no suspects, just a few tantalizing clues.

Two days after her disappearance, searchers found Coreen's cellular phone and MP3 player on a steel I-beam underneath the Route 25 bridge over the Saco River beside a picnic and rest area that straddles the Standish -Limington town line about 10 miles from her home. Several cryptic messages were scratched into the bridge's rusty girders: Coreen's birthdate and the date she went missing, "7/22/91-11/8/06," along with the words "Coreen Wiese RIP."

More than 100 law enforcement officials and volunteers have scoured the area, including the river, but they have turned up nothing else.

"There's just not much to work with," says Buxton police Officer Mike Grovo, who has spent thousands of hours trying to unravel the mystery as the lead case investigator in the eight-member department. "There's nothing definite saying she committed suicide. There's nothing saying that she wasn't abducted. The possibility exists for anything."

While authorities are tight-lipped about many of the details, they have been able to construct a rough timeline from eyewitness reports of Coreen's movements the rainy Wednesday she went missing. They know the bus dropped her off at Bonny Eagle High School, where she is a sophomore, at 7 a.m., but that she was not in homeroom 25 minutes later.

Coreen was later seen loitering near the Route 25 bridge, near a shallow section of the Saco River known locally as Limington Rapids. Nearby is Towneline Billiards, and police say the pool hall owner, Ken Leamy, gave her a ride to Jongerden's Market, a couple of miles down Route 25, and back. (Leamy has taken, and passed, an FBI polygraph test.)

In her conversations with the pool hall owner, Coreen concocted a tale to conceal her true identity. "She used a story of a family emergency," Grovo says. "She said her grandmother was sick and she was taking care of her . . . but that wasn't true. She was making up a lie to throw him off so people wouldn't be suspicious of her being out of school." Coreen also lied about her age on her MySpace blog, saying she was 17, says Grovo.

Coreen was last seen at about 4 p.m. walking toward the Route 25 bridge, underneath which her cellular phone, MP3 player, and the graffiti were later discovered.

Her parents say Coreen, who is 5 feet, 3 inches tall and 115 pounds, and has long chestnut hair and braces, was wearing blue jeans, a blue or gray hooded sweatshirt, and white sneakers, but did not have a coat. She has a mild form of epilepsy and was without her daily anti seizure medicine, Lamictal.

Coreen's disappearance has raised unsettling questions for police and her parents. Was the teenager waiting for someone and, if so, whom? Did she run away? Did she take her own life or did she attempt to fake her own death? Was she abducted, and did a predator leave her personal items and the scrawlings to make it appear she had committed suicide?

Grovo's gut tells him Coreen is still alive. "My sixth sense tells me she didn't walk into that river by herself," the 49-year-old career police officer says of the brown-eyed girl he has never met. "But unless she's in the river, someone had to be involved."

When Coreen first vanished, 25 FBI agents set up a local command post and tip line and joined state and local law enforcement officials and volunteers in the search. They used Global Positioning Systems and grid-mapping software as they trudged through woods near the high school and her home. Authorities put up roadblocks on Route 25 and conducted door-to-door interviews with neighbors. They brought in tracking dogs and dogs trained to find cadavers.

Once the electronics and graffiti were found, the focus shifted to the vicinity of the bridge and searchers fanned out as wardens used airboats and flew Cessna 180s over the river, but the water was too high and conditions too dangerous to use divers. By Christmas week, levels had receded and a nine-member scuba team embarked on a recovery mission but did not find a body.

At the same time, investigators analyzed messages stored in Coreen's cellular phone, the hard drive of her home computer, the contents of her school locker, and her MySpace account. "There was nothing to lead us to believe what happened to her," Grovo says. "That's what's puzzling."

Grovo has two three-ring binders bulging with interview notes that, together, are at least a foot thick.

"No matter where I go, what I do, I'm always thinking of her," he says of Coreen.

"It kind of haunts me because it could be my kids," adds Grovo, who has sons ages 10 and 17. "I try to look at it like what would I do to get the boys back?"

Wes Wiese has taken a leave from his job as a systems engineer and now spends his days trying to spread the word about his daughter's disappearance. Coreen's Missing poster is plastered on every tollbooth in Maine, and she is featured this month in a national campaign known as "18-Wheel Angels," which enlists the aid of truck drivers and business travelers to place missing-person posters along their routes.

In a Dodge Caravan emblazoned with the Missing posters, Cindy Wiese, 43, takes her 8-year-old son, Kyle, to and from his third-grade class at Frank Jewett Elementary School. She is afraid to let Kyle ride the school bus.

Last month the Wieses dipped into their savings to post a reward: $10,000 for disclosing Coreen's exact location and another $10,000 for information that leads to her safe return or the conviction of anyone responsible for her disappearance.

"We're going totally crazy," Wes Wiese says, "we don't know what to think."

The distraught father forces himself to make weekly checks of websites that cull gruesome tales about unidentified human remains found across the country. On the Internet site the Wieses have dedicated to the search, a countdown clock ticks off the days, hours, minutes, and seconds since Coreen went missing.

An honor-roll student and field hockey player who rarely missed school and who friends and relatives say dreamed of becoming a lawyer or journalist, Coreen has no history of depression or problems with alcohol or drugs. She had no steady boyfriend, although, classmates say, she had many male friends and a typical adolescent's interest in dating.

The morning she disappeared, one of Coreen's friends, Meghan Bridges, 16, of Steep Falls saw her at school.

"Coreen looked really, really sad like she'd been crying," Meghan says. "She said, 'You guys are such good friends. I don't know what I'd do without you guys.' . . . She sent text messages to her other friends saying the same thing."

Wiese fears his daughter might have been coerced into fleeing by someone or taken against her will; he refuses to believe she killed herself. "When they first told us they thought that [suicide] is what happened," he recalls, "we thought, 'No way. She had everything to live for.' "

The recent recovery of Shawn Hornbeck and Ben Ownby, allegedly kidnapped and held captive by a pizza parlor manager in Missouri for four years, gives the Wieses renewed hope that Coreen will eventually be found alive. Authorities are planning an extensive new search in the spring. Each morning, during the candle-lighting ritual, the family makes a short plea: Coreen, we light this candle with love for you. Please be safe and come home soon.

"I can't imagine going through four years not knowing where my daughter is," Wes Wiese says. "It's bad enough going through three months. It's like it just happened yesterday."

Anyone with information on the disappearance or whereabouts of Coreen Wiese is urged to call the Buxton Police Department, 207-929-6612 or visit coreenwiese.com. Stacey Chase can be reached at storychaser@earthlink.net.

(Correction: Because of an editing error, a story in Sunday's City & Region section about the search for Maine teenager Coreen Faye Wiese incorrectly stated how long two boys were missing in Missouri. Shawn Hornbeck was found four years after his disappearance; Ben Ownby was missing for four days.)