It's a total mystery, a baffling whodunit.
So baffling that investigators aren't even sure anyone has "dunit."
But it sure looks, on the surface, like foul play.
More than two weeks after 87-year-old Geraldine Jackson disappeared and her West Falls house burned to the ground, the lack of any other credible scenario points to the likelihood she may have been killed, her body dumped somewhere and then her house torched, investigators believe.
"You immediately suspect foul play," Erie County District Attorney Frank J. Clark said of the odd circumstances, including the facts that Jackson no longer drove and she didn't suffer from dementia.
"The suspicion, with her gone, is that she was the victim of foul play and that the house was burned to conceal evidence of criminal activity," Clark added. "That's a theory. Right now, there are no hard facts to determine what happened."
Authorities didn't know Jackson was missing until after her house was destroyed by fire on the morning of Dec. 22.
About a week later, 10 investigators spent seven or eight hours sifting through the rubble of Jackson's house on Irish Road, looking for any hint of her remains.
They found nothing -- not a tooth filling or a belt buckle or any evidence.
"There were no remnants of any human remains whatsoever," State Police Senior Investigator Richard Landahl said.
"We believe we've done everything possible to locate her in or around the residence," State Police Senior Investigator Edward J. Kennedy added. "But we're still not giving up on that."
Police and fire investigators have gone back to the scene, to look for the slightest physical clue that could help crack the case.
"It's a very time-consuming process," Landahl said. "They're looking for [anything] they can submit to a laboratory, to pinpoint a cause."
But finding that cause has proven elusive.
"It's going to be very difficult to come up with a cause or damage estimate, because of the extensive damage," Lt. Ron Kenyon of the Erie County Sheriff's Office said. "The rear portion of the house is essentially gone."
The questions won't go away:
Where would an 87-year-old woman with no car go, just three days before planning to celebrate Christmas with her family? Why would she just disappear?
Clark, other investigators and family members can't come up with any scenario to explain a voluntary disappearance.
How about an accident?
Clark suggested the woman could have gone for a walk and fallen or been stricken. But a search of the area by about 200 people last weekend found no such evidence. And even if that did happen, no one can explain how her house also could have burned down -- accidentally.
"The odds against that are almost astronomical," the district attorney pointed out.
So foul play becomes the most likely theory, by the process of elimination.
The investigation, of course, has been hampered by the incineration of parts of Jackson's home. Canvassing the home for the usual clues -- including physical evidence from any crime or clues like checkbook stubs or appointment-book entries -- became much more difficult.
Investigators have gone back to more classic methods.
"Anybody -- friends, relatives or neighbors -- you try to find them all and talk to them all, to make sure we didn't miss anything," Landahl said.
Authorities are treating this case as a possible homicide, until they learn otherwise.
"Police are pursuing various possible leads in the arson and the disappearance," Clark said.
As they would in any investigation, detectives are looking into any similar-sounding burglaries or home invasions recently in the general area.
No connection has been found to any other such cases, Kennedy said.
Investigators also have sought Jackson's dental records in case they need to compare them to any discovered body that could be Jackson's.