Sassafras has her own documentary, “The Search for Sassafras.” Sassafras has her own Web site, with her own set of Frequently Asked Questions (“Is it really Sassafras?”). Sassafras’s picture is prominently placed on about 6,000 fliers that have been distributed everywhere from Chevy Chase to Columbia Heights.

Sassafras is a beagle. She has been missing since April, when she got loose from a dog walker near the National Zoo. She has been spotted several times since: On, visitors can track her path as it dips in and out of the neighborhoods of Northwest Washington.

The sightings have been verified because the dog is being tracked by a professional, another dog — a golden retriever named Salsa who specializes in finding lost pets. Last week, after more than a month of cold trails, an update: Salsa tracked Sassafras to a Chevy Chase elementary school before losing the scent. The Web site quickly was updated with tips for people who might spot Sassafras: “You don’t look at her, you lie down flat, and you make soft noises.”

It all makes you think of the intensity of dog ownership, the resources that people will expend on their pets, the image of a carefree beagle scampering about the streets like Billy in “Family Circus.” A call is made to Beth Edinger, who owns Sassafras and has been responsible for the thousands of dollars spent on a missing 20-pound dog.

On a recent weekday morning, Beth and her husband, Jeff Abramson, sat in their Takoma Park bungalow and prepared for another round of flier-posting, targeting the area of the last confirmed spotting.

“We think,” Beth says, “that she’s sleeping during the day” and roaming at night, scrounging for food. One time Sassafras was tracked to American University’s campus, where a groundskeeper regularly puts out food and water for local dogs. Beth and Jeff have a “Sass Cam” installed near the water bowl in case she comes back.

They have a Sass Phone, dedicated to receiving dog information. They tried “Find Toto,” a service that places robo-calls to households in neighborhoods where lost dogs have been spotted. (They try to accomplish most of this work during odd off-hours so as not to upset their 2-year-old daughter, Kalliope.) They spent $2,000 to bring a professional tracker up from Georgia; he worked for 24 hours straight with his dogs and got no leads. Now they’re working with a woman from Baltimore, Salsa’s owner, who has launched multiple tracks. One time, she donated her services.

This dog has come to mean something to people, triggering memories of their own dogs or their own childhoods. Strangers — complete strangers — have volunteered to tramp through neighborhoods for hours, searching and passing out fliers. Someone built them a blog. One volunteer who knows something about the T-shirt business had a bunch made, all with a photograph of Sassafras, raising one white paw quizzically in the air.

An American University graduate student witnessed the unending faith that Beth and Jeff had in their dog, and decided he wanted to make Sassafras the subject of his documentary project for a class. “Your initial reaction is to be amazed that someone would go to these lengths,” says the student, Jon Hussey. “But then you understand that there really is an emotional core involved.”

“People ask, ‘Why don’t you just stop?’ ” Beth says. “I don’t know how to stop. I know my dog is alive, and she’s still my dog, and we promised that we would take care of her.”

“If she were dead, I would know how to grieve,” Jeff says. People close to him have died. If grief were the emotion that was called for, he would know what that looked like and how it works. But the required emotion now is something that is far riskier than grief: Hope.

They can have closure, or they can have hope. They can stop looking, and they can worry that the day they stop looking is the day they would have found her.

There is a reason that stories about dogs and pictures of dogs pull at the hearts of so many people. People say they are like family, but lacking the ability to criticize, judge, talk back or neglect, they are nearly the opposite. Instead they can be the receptacle of emotions that are too raw for human consumption. Everyone can admit the profound sadness of a lost dog.

David Conn is the groundskeeper at American University. He’s a tall man, scruffy, with a gray ponytail. He is the one who puts out the water and the treats for the dogs, the ones that first drew Sassafras to campus in July. He is the one who gave Edinger permission to put up the camera. Sassafras is his cause now. He puts up fliers. He owns a Sassafras T-shirt.

Conn’s son died in June. An accident, horrible, unexpected. The day Beth posted fliers would have been his birthday. He would have been 26.

“Sass has given me something to focus on” in these months of unending grief, he says. “As much as I can focus on anything else.”

He knows that what Beth and Jeff are doing sounds kind of crazy. But he supposes there are worse things to spend money on.

“And,” he says, “if you ever saw the video of her playing with the baby . . .

This is not the documentary, but rather a home movie that Jeff uploaded onto the Web site in the early days after the dog disappeared. In it, Sassafras and Kalliope are playing tug of war with a dish towel. The dog is shaking it back and forth, and the baby is laughing ecstatically.

If you have seen this video, then you know how precious the things are that we love, and the lengths to which we would go to have them back again.