As friends, family and volunteers searched in bitter cold and rugged mountain terrain Thursday for Meredith Hope Emerson of Buford, a 24-year-old hiker not seen since New Year's Day, another search was under way for an aging backpacker now wanted for questioning in her disappearance.

Law enforcement officials said at nightfall that they wanted to talk with Gary Michael Hilton, 61, who was seen by other hikers in Vogel State Park as he and Emerson walked with their dogs up Freeman Trail on Blood Mountain.

Family

Meredith Emerson

Police

Gary Michael Hilton, 61, was seen by other hikers with Emerson at Vogel State Park, according to police

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Single-digit temperatures, snow and biting winds have challenged the searchers since Emerson's car was found early Wednesday morning.

Authorities said the woman's water bottle and the leash for her black mixed-breed dog, Ella, were discovered a few hundred yards from her car. Hilton had his dog, Dandy, with him.

Emerson, a sales manager for a Winder packaging company and a 2005 graduate of the University of Georgia, grew up in Longmont. Colo., at the base of the Rocky Mountains. Her parents, Susan and Dave Emerson, flew in Wednesday from Longmont to join the search.

Little is known about Hilton. He was convicted of two felonies — one for the possession and distribution of marijuana, another for theft by taking. According to public records, his last known address was on 11th Street in Atlanta in 1999.

Kimberly Verdone, an investigator for the Union County Sheriff's Office, said Hilton is a "person of interest" in Meredith Emerson's disappearance because he was the last person seen with her.

Police said he was last spotted driving a white Chevrolet Astro van with license plate number 76APZ. He also has a 2001 white van with plate number AFQ1310; both vehicles are registered in DeKalb County, police said.

Police have yet to say whether they believe foul play is involved in Emerson's disappearance — only that they have no evidence to support that conclusion.

"Meredith's middle name is Hope, and that's exactly what God grants us," said Peggy Bailey, Emerson's godmother, who is acting as the family spokeswoman and was at the search site Thursday.

Bailey said Emerson's parents were alarmed when they heard that a man was seen with her just before she disappeared.

Emerson's friends described her as fit and familiar with the outdoors. Martial arts practice and hiking a couple of times a week put her 5-foot 4-inch, 120-pound frame into wiry shape.

"She's athletic, very athletic," said her roommate, Julia Karrenbauer. "She runs all the time, walks all the time, hikes all the time. If faced with a situation, I'd be confident in her abilities."

But Emerson's athleticism led some of her friends to fear the worst — that if she was just lost or hurt, she would have made it off the mountain or been found by Thursday afternoon.

"Best-case scenario, she's not on that mountain," said Chris Hendley, her former boss from The Arena at Gwinnett Center. "Most of us are certain she's not lost."

Emerson went hiking with her dog about 11 a.m. Tuesday on the six-mile-long trail, police said.

Before Hilton was connected to the case, several people told investigators they saw her with a gray- or silver-haired man who had a backpack and wore a yellow jacket with black elbow patches and stripes, Verdone said. Police say Hilton is about 5 foot 10 inches tall and weighs 160 pounds.

In addition to Emerson's water bottle and the dog leash, searchers also found a police baton of some sort, but it hasn't been tied to Emerson's disappearance.

On Thursday, volunteers who knew the 20,000-acre park and its mountains best and could give medical attention were sent out first in "hasty teams," said 1st Lt. Brad Niebrand of the Union County Fire Department.

By noon Thursday, about 100 people had assembled at the state park's visitors center, hoping to assist with the search. Old Army fatigues mixed with hunter's camouflage among the assembled volunteers.

Most didn't know Emerson personally. People brought their dogs, hoping to find a scent. Some who showed up in jeans and light jackets were turned away.

The mountain was cold New Year's Day and colder Thursday morning.

Atlanta set a record low for Jan. 3; law enforcement officers estimated the temperature on Blood Mountain dropped below zero on Wednesday night, and similar temperatures were expected Thursday night.

"It's a very difficult trail, especially when it's covered with snow," Verdone said, noting that the area got 1 to 1 1/2 inches overnight.

As dusk approached, some grumbling emerged from those still at the bottom of the mountain who had not been rounded up into a search team.

But law enforcement officials initially wanted to give the heat-sensing equipment on the Georgia Bureau of Investigation helicopter a chance to work without the confusion of other warm bodies on the mountain, Niebrand said.

Later in the day, officers expressed concern about potentially losing someone else on the mountain during the search. The scale of the search was unprecedented, Niebrand said.

Volunteers were eventually replaced by a team of 18 officers from Gwinnett County, who planned to use dogs to continue the search after dark, Niebrand said. It took hours just to pull the volunteer search teams from the mountain.

Some of them were "pretty deep in there," Niebrand said.

Meanwhile, miles away, authorities investigating the presumed double murder of an elderly North Carolina couple were closely following the search for Emerson.

In that case, a surveillance video at a bank in Ducktown, Tenn. — about an hour away from where Emerson was last seen — captured someone wearing a yellow jacket using the couple's ATM card on Oct. 22.

Nothing else is known about the suspect, Young said.

"Right now we don't see a correlation, but the yellow jacket certainly raised a flag," he said. "They call these things clues."

The search for Emerson will continue today. Anyone with information on the case is asked to call the Union County Sheriff's Office at 706-439-6066.

— AJC staff writers Ken Sugiura, Christian Boone and Brandy Wilson and researcher Sharon Gaus contributed to this story.