SANDPOINT - Scientists were unable to extract human DNA from the skeletal remains discovered at the bottom of Priest Lake, Bonner County Sheriff's officials said on Tuesday.

Three samples were recovered from the fragile remains, thought to be between 50 and 100 years old, last May. The remains were located in 322 feet of water off Eightmile Island.

Ralston & Associates, an underwater search-and-recovery company from Kuna, originally discovered the remains with side-scan sonar in 2004 during the hunt for a Washington state man who went missing while sailing the lake.

A small wooden rowboat was discovered near the remains, although it yielded no identifying characteristics.

Ralston & Associates returned last spring armed with a remotely-operated submersible vehicle, which was used to recover the samples.

Over the past four years, sheriff's officials have been working to bring closure to as many as 12 missing persons cases on Priest Lake dating back to the early 1900s.

Sheriff's officials hoped to develop a human DNA profile from the samples pulled from the inky depths off Eightmile so they could check it against samples provided by relatives of people who have gone missing on the lake.

"The outcome of this investigation is regrettable due to the fact that there are so many surviving members who have lost loved ones in Priest Lake. It was my intent to simply identify and provide closure to the families potentially affected by this incident," Sgt. Gary Johnston said in a statement.

Ralston & Associates teamed up with Silvia Pettem, an author and researcher who penned "Someone's Daughter: In Search of Justice for Jane Doe." The book chronicled efforts to unravel a murder mystery in Boulder, Colo.

Pettem pored over online resources in addition to microfilms of old newspapers to help identify the remains at Priest Lake.

"Although this is a disappointing ending to the case, I've been impressed with the professionalism of the Bonner County Sheriff's Office. I also have formed personal relationships with several of the families of the drowning victims and regret that none, at this time, have the closure they have been seeking," Pettem said in a statement posted to her website on Tuesday.

Although the Eightmile investigation has drawn to a close, sheriff's officials vow to keep investigating all leads involving missing persons in Bonner County.