BILLERICA — Fortunately for Willow, Maureen Ray isn’t afraid to get dirty.

The Billerica animal control officer crawled Army-style through 30 feet of mud and muck in a narrow drainage culvert on Friday evening to rescue the lost 3-year-old pug.

The dog’s owner, Maria Watson of Chester, N.H., said the incident “really restored my faith in animal control and humanity in general.”

Willow’s adventure began at about 2:30 p.m. Friday. Watson said her son’s girlfriend took three of Watson’s dogs to her aunt’s business, You Dirty Dog on Boston Road, to get a grooming.

But Willow is often hesitant and scared of strangers, and as soon as she was taken out of the car she pulled back, slipped out of her collar and ran off.

Watson said she never found another dog that ran off about three years ago in New Hampshire, and never got much help from animal control officers there.

“I was hysterical,” Watson said. “She’s my baby. I couldn’t face this again.”

Despite having her doubts that officials would do much to help, Watson contacted Billerica and Tewksbury Animal Control via the Police Department, and sent several family members and friends to Billerica to search.

“Really, due to my past experiences, I didn’t have much hope,” Watson said.

Ray soon called her, though, and reported that she was already in the area searching, so Watson got her in touch with family members who had traveled to Billerica to join the hunt.

Searchers got a tip that someone saw a dog running into the woods in the area of Sprague Street and Boston Road, not far from where Willow went missing, and while checking that area Ray noticed a drainage culvert that runs under Sprague Street, according to fellow Animal Control Officer Christine Gaultieri.

Ray used a light to check the culvert, and when she saw the dog staring back at her she crawled in, Gaultieri said.

Watson said her family members at the scene estimated that Ray crawled at least 30 feet through the culvert on her stomach as Watson’s family and friends blocked the other side of the culvert, which was too narrow to crawl through.

“My husband said Maureen, without hesitation, got down and Army-crawled all the way into the pipe,” Watson said.

Watson said she heard Ray even broke her phone in the process since it got wet in the culvert.

Ray emerged from the pipe covered in mud about 6:30 p.m., with a mud-covered Willow in her arms.

Animal Control tweeted out a photo that was taken of the two shortly after they emerged.

Gaultieri said Ray was off duty Saturday and not available to comment.

Watson called the rescue “amazing” and said she later heard Ray is a fellow pug owner, who had no intention of giving up before Willow was found.

“She was an angel,” Watson said of Ray. “I was already preparing myself for the worst, but she really restored my faith in animal control and humanity in general.”

Watson said Willow was initially hesitant after returning home, but that she was back to her normal self on Saturday.

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