A Missouri man who took his rescue dog to the vet for an X-ray was left stunned when the results revealed something disturbing about the pet's past.

Charlie, who asked not to be formally named, knew from the minute he laid eyes on Momo at an adoption event out of state that she was the dog for him.

"I was looking through their list of dogs available for adoption online and she immediately stood out to me as a world-weary older dog that needed a peaceful, quiet, and loving home," he told Newsweek.

"Then I went to meet her at an event they had their dogs at and she and I clicked right away. Her foster mom was surprised by how quickly she seemed to warm up to me."

Charlie didn't know a whole lot about Momo's life before they met. Momo was seven years old when he adopted her. Momo was originally picked up as a stray but there were signs of mistreatment and a vet told him it was likely she was used for breeding.

Four years on from her adoption and Momo lives the kind of life every senior dog deserves. "Her favorite thing is really just slow, leisurely walks with plenty of things to sniff and watch," Charlie said. "She also loves to sunbathe in the backyard, despite her black fur."

Momo's life is pretty idyllic these days but Charlie was recently given an alarming reminder of the difficulties his beloved rescue pup experienced in their younger years. Charlie had taken Momo to the vet after she began to experience mobility issues.

The subsequent X-rays not only revealed Momo was suffering from arthritis and hip dysplasia, but also something else.

The X-rays highlighted a series of small dots throughout her body along with a more significant object "in her hip near her spine." That object was a bullet, while the small dots were birdshot.

At some point before Momo came into Charlie's care, she had been shot several times.

Thankfully, the birdshot and bullets were causing Momo no pain, but Charlie acknowledges the bullet was "pretty close" to his dog's spine. A little closer and she might not have been here today.

"I was pretty shocked and saddened," Charlie said.

Though the vet treating Momo didn't have any theories, Charlie found plenty of people willing to weigh in on what happened after he posted pictures of the X-ray to Reddit.

Charlie has asked that his Reddit handle be omitted from this story.

"The vet didn't have any theories, but some of the comments on the post have guesses. The small dots could be BBs from many repeated shots, or pieces of buckshot/birdshot from one blast," he said. "The 'bullet' in her hip near her spine is actually a field pellet from an air rifle."

As to how Momo ended up being shot, theories range from the seemingly logical to the more dark and disturbing. "Some people guessed it could've been a farmer trying to scare her off their land, others thought it might be some kid using her for target practice," Charlie said.

Whatever the truth, the main thing for Charlie is that Momo is here now and happy.

"I was just happy to hear that it's not causing her any pain, and also glad that she's got a nice peaceful life now," he said.