Few area cases have confounded authorities more than the disappearance of a West Brandywine Township nurse and mother seven years ago.

About 5 a.m. on Aug. 23, 2009, guests partying at the home of a former Philadelphia 76er were the last people to see 29-year-old Toni Lee Sharpless before she vanished, leaving an incomprehensible lack of clues in today’s electronic age.

Searches from Philadelphia to Sharpless’ West Brandywine Township residence, the distribution of hundreds of fliers, and countless news broadcasts came up empty. Equally unsuccessful was the dredging of a section of the Schuylkill River in case Sharpless’ black, 2002, four-door Pontiac Grand Prix had veered off the road near Willie Green’s former Gladwyne estate.

Sharpless’ parents, Donna and Peter Knebel, have struggled to keep the case alive. They have conducted interviews, distributed fliers, participated in searches, and even appeared on national TV.

The Knebels, who have been raising their now 18-year-old granddaughter, desperately want closure, and two people have consistently aided in that quest: West Brandywine Township Police Chief Walt Werner and Eileen Auch Law, a Chadds Ford-area private investigator.

Werner, who said he has contact with the Knebels a couple of times a year, is convinced that the case will be solved eventually. “Somebody out there knows something,” he said. “We just need to find that person.”

The police chief said Sharpless’ DNA was entered into a national database as was her license — Pennsylvania DND-7772. Her car was never found. Neither was her phone, which was never used, nor her credit cards, which also were not used.

In fact, the only evidence police said they received came about two weeks after Sharpless vanished when her Grand Prix’s license plate was recorded by an automatic license-plate reader in Camden.

In the seven years since, Werner said many dozens of leads have surfaced; unfortunately, some — such as the caller who erroneously claimed to be an agent with the Canadian equivalent of the FBI or the man who posed as the sheriff of Divide County in North Dakota — have been hoaxes. Most have been simple misidentifications, he said.

So far this year, he said his department hasn’t received any calls, but he said the anniversary typically prompts some. He said he has forwarded many leads to Law.

“She’s been an enormous help in this investigation,” Werner said, explaining that she has resources and connections that his small department does not have.

Law said she has been committed to the case since she first interacted with the family about a month and a half after Sharpless disappeared. Law said in more than three decades of missing-person’s cases, she had never before experienced the kind of impassioned plea she heard from Sharpless’s daughter. “Please find my Mommy,” the 9-year-old begged her.

The girl’s words resonated and stuck, said Law, who has been working pro bono ever since. She set up a Toni Sharpless Facebook page and a Web site — www.MissingToniSharpless.com — to generate leads. She keeps a map in her office with dozens of pins marking each time someone reportedly spotted Sharpless, sightings that have stopped in the past couple of years, and she has traveled from Canada to Florida to track down information.

Law said she starts her day by checking the many alerts she has set up on her computer with phrases ranging from “woman’s body found” to “sale of 2002 Pontiac Grand Prix. “ She said she gets about 35 notifications a day in response to the alerts and often calls medical examiner's offices or police departments to rule out Sharpless.

“My heart is always in my throat with each call,” she said. “Until I take my last breath, I will never give up … Her family has become my family. They deserve to know what happened.”

According to police reports, the evening before Sharpless disappeared, she decided to go out with a longtime friend, Crystal Johns. Her parents said they welcomed the news because their daughter, a single mother, had been working so hard that she had virtually no social life.

Johns told police that the pair was invited to Green’s Main Line house after meeting him at G Lounge, a Philadelphia nightclub. Johns said Sharpless apparently had too much to drink, and they were asked to leave his Lower Merion Township residence. Once outside, Johns suggested that Sharpless, who had become uncharacteristically belligerent, should not drive. The two argued, and Sharpless drove off alone, stranding Johns.

In interviews, Johns called Sharpless’ behavior highly unusual. Sharpless’ family said it likely resulted from a mix of alcohol, sleep deprivation, and medication for bi-polar disorder, an illness she had finally brought under control after struggling for years to get a diagnosis.

Police said Sharpless’ last use of her cellphone occurred a few hours before she left Green’s home when she texted her daughter and urged her to get a good night’s sleep and told her that she loved her.

Law said Sharpless’ impaired condition could have made her vulnerable to foul play. She said there are more cases than one would imagine involving people who have been found years after being abducted.

Werner agreed, noting that every year a couple of cases generate national headlines when someone who has been missing for a long time suddenly surfaces. “We’re always hoping for the best,” he said, adding that he’s convinced that someone has information that would solve the mystery.

“We’re hoping for that one key lead,” he said. He added that perhaps the passage of time would prompt someone to come forward for the sake of the family. “We absolutely want to help them get closure,” he said.

Law said that even without new leads, she keeps busy ruling out old ones. She said some of the tips have contained information that suggested insider knowledge of the case.

For example, one anonymous letter postmarked in Trenton that Law received on Dec. 1, 2012, alleged that Sharpless died in a fight with an unnamed Camden police officer. The writer, who knew the Grand Prix’s vehicle identification number, claimed to have received $5,000 to take Sharpless’ car from Brooklawn, a borough in Camden County, to a Boston chop shop.

Law said that although the letter also had some information that didn’t appear credible, some of its contents were plausible and were echoed nine months later in an email she received. Law said she turned the letter over to police and isn’t certain what was done with it.

She said it’s unfortunate that the case has involved law enforcement from so many separate jurisdictions, including the Lower Merion Township Police Department, the West Brandywine Township Police Department, and the New Jersey State Police.

“I wish we could just get everyone in the same room to share information,” she said. “Maybe someone would come up with something that no one had considered before.”

Law said the more people who post Sharpless' story and photo online,  the better. "The person or persons with knowledge of what happened are out there somewhere," she said.

Anyone with information should call West Brandywine Township Police at 610-380-8201 or Law at 1-800-796-9042.