It was 11 a.m. on a Wednesday when pet-sitter Chris Scherrer and four of her charges were descending a trail into the woods behind Cinnaminson High School.

Off-leash in the secluded area, the group approached a creek at the bottom of the trail.

That's when Scherrer noticed that one of the dogs, Nessie, a 65-pound 5-year-old, wasn't with them anymore.

Through the thicket, Scherrer screamed for the dog, but she was gone.

"I took my eyes off her for less than a minute," she said.

It was time to call Nessie's owners, but the couple - who for years have also taken care of Scherrer's dogs - was at Virtua Voorhees Hospital, where their son, Dylan, had just been born.

"She's crying, I mean, just devastated," said Shawn Munion of Westmont. "I couldn't understand her. And she finally screams, 'Nessie's gone!' And I said, 'What do you mean she's gone?' "

And just like that, a lost greyhound became the focus of a recovery mission that mobilized neighbors, business owners, and volunteers in the South Jersey community, as well as greyhound lovers as far away as Staten Island and Delaware.

Statistics were not in their favor. Every day, desperate pet owners post pleas on Facebook and telephone poles looking for lost animals, but greyhound experts say the slender breed is hard to track because of its racing ability. In three strides, a greyhound can reach a speed of 35 m.p.h.

Munion and Scherrer blamed themselves for Nessie's running away. Greyhounds are sighthounds, with keen vision for moving objects, so advocates say they shouldn't be unleashed. They think Nessie was lured by a squirrel or deer.

"It was my call. I told Chris it was all right to unleash her. I've always walked my older greyhound, Bobby, without a leash," said Munion, a driver for Aramark.

First, Munion drove to the tree-lined streets near the high school. Then he called Greyhound Angels Adoption in Millville, N.J., the rescue group that had paired the family with Nessie the year before. Scherrer posted a picture of Nessie on her Facebook page.

By 4 p.m., a woman phoned Munion to say she'd seen Nessie running behind a nursing home a few blocks from where she'd disappeared. Munion raced over, only to find a flock of turkeys.

Early Thursday morning, Munion visited his newborn son and wife, Crystal, and then returned to the search. Around 9 a.m., a man called: "Your dog is drinking water from a container in my yard." But Munion missed her again. Later that day, he brought his wife and son home.

Around noon, greyhound advocate Julie Costello of South Philadelphia saw pleas for Nessie on Facebook. She called Kathy Wagner, a disc jockey at WMGK-FM who often teams with Costello to find lost greyhounds.

Wagner immediately created the Nessie the Lost Greyhound page, added a post on the Greyhound Amber Alert page, and set up a group text. "Getting the word out within 24 hours is important," Wagner said.

Scherrer's house in Cinnaminson turned into headquarters for volunteers. People delivered heavy-duty tape, staple guns, and plastic sleeves (in case of rain) for the 500 printed fliers that were hung on telephone poles. Fliers also were distributed at Walmart, Sam's Club, PetSmart, a dollar store, gas stations, and the Riverton Country Club.

By Friday, when Nessie was spotted drinking from the creek alongside deer, Costello became worried she'd found a pack. "If she'd joined a pack, she'd start to ignore her owner's voice and instead, focus on finding water, food, and shelter."

But by 10 p.m., a woman called to say she was in her car, following the greyhound up busy Riverton Road, and was heading toward Route 130, an even busier one. Then Nessie darted behind the library and ran past a bar - and the woman lost her.

On Saturday, behind a shuttered senior home, Costello cooked hot dogs on a portable grill, hoping to entice the dog. She set up a 6-foot-long cage trap - which yielded a raccoon.

That night, volunteers, some walking their own greyhounds, fanned out across the neighborhood with flashlights. Motorists pulled over, asking for fliers. A man reported seeing Nessie running near the high school.

Costello pinned every Nessie sighting on a Google map. "The good news was she was traveling in a one-mile circle."

Meanwhile, Munion was splitting his time between home and the search. "I was wrestling with two emotions: being a first-time dad and losing my baby girl."

By Saturday night, he grew more frantic. The winds were whipping, and the temperature plunged into the 30s. Residents left their garages open for Nessie. One man, a hunter, set up his night-vision camera.

Finally, on Sunday, Colleen Gallagher, a nursing student at Camden County College, was doing homework at the kitchen table. The night before, her family had left open their garage door, which borders the high school property.

Through the sliding doors, Gallagher spotted Nessie lapping water from a puddle on the cover of their in-ground pool.

"I started screaming, 'There's the greyhound!' " Gallagher said. Nessie, still wearing her harness and tags, was trembling and made little attempt to run. She'd lost four pounds and was covered in ticks.

Munion was in Acme when he got the call. "I just cried."

It took four days, and Nessie was exhausted (but fine). "I didn't even meet half the people who helped in the search," Munion said. "I'm just beyond grateful to this community.

"I have quite a story to tell my son."