Warning: This story contains images some readers may find disturbing.

The Ontario SPCA and Ontario Provincial Police say they are conducting an investigation after images of three sick-looking horses were shared on social media Friday.

The purported deteriorating condition of the animals has been grabbing the attention of people in the community of Waterford, Ont., for months, according to local residents.

That concern escalated into protests at the property on Saturday, after local horse owner Natalie Tupper saw them on Friday night and shared several photographs online.

“I was definitely at my wit’s end with nothing being done,’ Tupper told CTV Kitchener during the protest outside the property.

Tupper says that she drives by the property every day and had noticed their condition worsening over time.

“I feel for these people,” she said of the horses’ owners. “My initial reaction was to stop and offer help but they wouldn't talk to me,” she added. “All these people here just want to see these horses saved.”

Kristi Dredge, who owns horses in the area, was at the protest. She said she too has seen the horses’ conditions decline recently.

“Their coats changed,” she said. “They're very dull ... They're very thin. You could see their backbone(s) and their hipbones. Definitely a loss of weight.”

Kathy Douglas lives next door to the property.

“I love animals,” she told CTV Kitchener while choking back tears. “How they went from looking healthy to where they went, how they just (became) skeletons, it's just horrible,” she added.

On Saturday morning, a veterinarian arrived at the property to assess the situation and one of the horses was euthanized.

Const. Ed Sanchuk of Norfolk County OPP was at the scene.

“Speaking to the homeowner, I was advised that the horse has been ill for quite some time and he indicated that the horse was supposed to be euthanized as of Thursday,” Sanchuk told CTV Kitchener.

Sanchuk said allegations concerning the mistreatment of animals must be taken seriously and that police seek “expert opinions to assist us with our investigations.” He added that the two remaining horses were under the care of the local humane society.

No charges have been laid.

OSPCA: 'Images ... do not share the full story'

The Ontario SPCA said in a written statement Saturday that it is aware of the situation and conducting an “open investigation.”

“Ongoing action is being taken to help these animals,” the OSPCA said. “The Society would like to reassure the public that we have been out to visit the animals several times and have addressed any concerns reported.”

The Ontario SPCA added that “images on social media do not share the full story.”

“We recognize the pictures shared on social media of the horses are concerning,” the statement goes on. “The horses involved are sick and have been under ongoing veterinary care. Whenever we have visited the property to address concerns brought forward, the owners have always worked well with us to ensure the animals are getting the care they require. The horses have always had food, water and shelter available to them when we have visited the property.”

The horses’ owners declined to speak to CTV Kitchener on camera Saturday, saying they were too distraught after losing one of their animals.