The dog owners were strolling with Toby, their new Labrador retriever mix, near railroad tracks in Elk River when a train horn suddenly blasted.

The sound startled the skittish rescue dog. He jerked the retractable leash from their hands and "took off like a little rocket," said owner Jen Lehman, who trailed him for the next day and a half without success.

While posting Toby's description online, Lehman and her partner learned about the Retrievers, a Twin Cities-based nonprofit dedicated to helping owners find their lost dogs free of charge.

They completed a form and got a call from Natalie Wicker, a Retrievers case manager from Hugo. The search continued for another month, guided by Wicker, until a terrified Toby was captured during a late-night stakeout.

"This was all foreign territory to us," Lehman said. "[The Retrievers] were absolutely unbelievable."

The nonprofit was started in spring of 2014 by four longtime volunteers with a dog rescue organization. The group became experts in what to do when a pet ran away, but realized the public didn't know how to respond when it happened, said Devon Thomas Treadwell, a founder.

"You can be so helpful if you're prepared," Treadwell said.

In their first year, the Retrievers took on 200 cases. By sharing advice and using high-tech tools, they found the lost dogs in about two-thirds of cases, Treadwell said.

The organization relies on donations, along with the help of 17 dedicated volunteers.

It feels like a part-time job, said Wicker, who spends 10 to 15 hours a week on a case, hunting until the dog is found.

"I had no idea this organization existed until I lost my own foster dog," Wicker said. "Now, this is how I want to give back."

Finding Fido

Dogs run away for many reasons. But as rescue groups have gained traction, transporting more dogs from shelters to foster homes, the number of runaway hounds has increased. Rescue dogs are nervous and in unfamiliar places — given the chance, many will bolt, Treadwell said.

Once on their own, dogs "are often in a state of anxiety," and won't even respond to owners' calls, she said.

Getting the word out is key. When the Retrievers get a case, they advise owners to stop looking for their dog and start making big, bright signs to put at intersections. They can also check "lost dog" websites, post information on Facebook and look on Craigslist, she said.

Once there are sightings, Retrievers track them on a Google map and put food out to get the dog to establish a home base. Using a motion-detector camera and setting a trap — there are several kinds but all are humane — are next steps.

A Retrievers founder designed a special electromagnetic trap that opens and closes when a beam of light is intercepted, like a garage door. The Retrievers have shared the invention, Treadwell said.

An important piece of the job is maintaining owners' morale. Locating a dog, deceased or alive, can take months. Volunteers never give up, Wicker said.

"If you truly want your dog back, you have to put out a tremendous amount of work," she said.

Toby, the Lab mix, was caught through an elaborate ruse: owners Lehman and Rachel Haemig brought Toby's brother, Bowser, to where Toby was spotted. Bowser marked the area with urine. Enticed by Bowser's familiar scent and food, Toby walked into the trap.

Lehman said she would've searched for Toby no matter how long it took. Lehman and Haemig ended up adopting Bowser, too.

"I couldn't see not having both of them," Lehman said. "They bring absolute joy."

Erin Adler • 952-746-3283