Images of dead horses found shot and killed in Alberta's foothills are spurring anger and a call for action.

Four more horses were found shot on Thursday near Sundre, about a 90-minute drive northwest of Calgary.

Earlier this month, three others were found dead, making for 20 in the last two years.

The Wild Horses Society of Alberta has posted a $6,500 reward for information leading to the capture of the killers.

"There's absolutely no sport in that whatsoever. It's just killing for the sake of killing," said society spokesman Bob Henderson.

However, law enforcement officials aren't waiting for information to come to them. They went out in the field to investigate.

"I've got the bullet, I've got the DNA. If sometime I can get the gun, I can match all three," RCMP Cpl. David Heaslip, a livestock crimes investigator, told CTV News.

"Get the gun, get the guy."

Leaning against a pine tree, wearing a cowboy hat, Heaslip said: "I have a certain passion for getting bad guys who do stuff like this. And putting them where they belong."

The horses are believed to be the descendants of domestic animals used in local logging and mining operations in the late 19th and early 20th century.

Over the years, there have been unsuccessful attempts to round them up.

Courts can impose a fine of up to $2,000 on those convicted of illegally killing the animals.

The society is lobbying the Alberta government to strengthen legislative protection for the animals.

With a report from CTV's Sarah Galashan