MISSOULA, Mont. -

Few leads and no answers. North Dakota investigators hope a six-month-old cold case doesn't dead end in Butte.

They're retracing the route taken by an 82-year-old North Dakota woman missing since last October.

Investigators Dan Hillebrand and Larry Hoffman drove about 1,000 miles from Grand Forks County. But the trip doesn't stop there. They'll back track over the 118-mile stretch from Missoula to Butte, in search of anything that can help them find Florence Dumontet.

?We?re trying to develop a plan as to how best to search for Miss Dumontet,? said Hillebrand.

Dumontet went missing more than six months ago. Family members say she and her poodle ?Peaches? were headed from their home in Grand Forks, ND, to Seattle, WA.

?She never arrived, so we started the investigation of a missing person,? Hillebrand said. He says that investigation led them to a Town Pump in Butte. ?She leaves the store and nobody's seen or heard of her since.?

Surveillance video from gas stations in North Dakota and Butte prove where Dumontet stopped during her trip. Investigators say they know the woman pictured in surveillance footage is Dumontet because of the Lincoln Mark pickup truck she was driving.

Hillebrand says it?s a rare vehicle, ?On our trip out here, the thousand miles out here, we hadn't seen one.?

Though there's no sign of that truck or even one like it, investigators aren?t giving up. They're meeting with Montana law enforcement officers to ask for help.

?People don't hear anything they tend to think that maybe she's been found,? Hillebrand said. ?We're going to try and tell the people she's still out there and we're still looking.?

They know it's a large area to cover, and they may have to drive a thousand more miles, but they'll do what it takes to find out what happened to Florence Dumontet.

Florence Dumontet is described as 5-feet-tall and weighs about 150 pounds. She has white hair and blue eyes. Dumontet?s truck is a 2008 black Lincoln Mark LT crew-crab pickup. She was last traveling with her cream-colored toy poodle.

Anyone with information about Florence Dumontet is asked to call local law enforcement.