PRINEVILLE, Ore. -

Crook County sheriff's deputies said Friday they have found three more horses shot and killed in the Ochoco National Forest east of Prineville, bringing to six the total of wild horses found in the past month that apparently were killed and left in similar fashion.

Authorities said in mid-March turned to the public for tips in hopes of finding whoever had shot and killed three wild horses east of Prineville ? one of which was pregnant and accompanied by her year-old foal, which was found unhurt.

Crook County sheriff?s Deputy Brian Bottoms made the grisly discovery around 2 p.m. March 14 while on patrol in the Ochoco National Forest about 18 miles east of Prineville, said Det Sgt. Travis Jurgens.

"It was definitely an intentional shooting of the three horses," said Jurgens. "We have undetermined number of rounds that were fired at this point."

Bottoms found the first dead horse along a spur road off Forest Road 150 in the Douthit Creek drainage, near the Ochoco Ranger Station, Jurgens said. Further investigation led to the two others, for a total of two stallions and a mare.

The mare appears to have been pregnant and had a foal about 1 years old with her at the time, nudging her, trying to get her back on her feet when the deputy arrived, Jurgens said. The foal was unhurt but left abandoned by the mare?s death.

?It was determined that all three horses had been shot and killed with a firearm for no apparent reason,? Jurgens said, adding that Bottoms was able to obtain evidence by having come upon the "fairly recent" shooting scene.

In the week after the initial discovery, deputies found a fourth wild horse that appeared to have been shot and killed, along Forest Service Road 42.

During further investigation, deputies have found at least two other carcasses of horses, believed to be wild, that had been dead for quite some time.

Deputies are working with Forest Service law enforcement to follow up on leads from the public. Deputy Brian Bottoms said Friday they are still encouraging everyone to provide information until the case is solved and the perpetrators are arrested.

Anyone with information was asked to contact the sheriff?s office at (541) 447-6398 or contact the Crime Stoppers Tip Line at 1-877-876-TIPS. You can remain anonymous and you may be eligible for a cash reward.

As a member of the Central Oregon Wild Horse Coalition, Krista Lee hung posters around Prineville last month, asking for the public's help in finding whoever shot the horses..

"I think that it's just very shocking," said Lee. "There are so many people that love and care about these horses -- it's like having someone come into your own home and kill a family member."

What makes Lee even angrier is that this is not the first time an attack like this has happened. Since 2002, Lee said there have been similar attacks in the area.

"Anywhere from one to three horses being killed per time," said Lee. "And they're still doing it."

Lee said she and members of the coalition are working hard to get the word out to the public, in hope of finding whoever is responsible for hurting the innocent animals.

"If there's a horse you want to ride to Hell and back on, these are the horses you want to do it with," said Lee. "So to remove them or harm them is beyond possible thinking."

The Central Oregon Wild Horse Coalition also was offering a reward of $1,000 for information leading to the arrest and conviction of whoever shot and mutilated the horses.

The Humane Society of the United States also announced it is offering a reward of up to $2,500 for information leading to the identification, arrest and conviction of the person or persons responsible for killing the horses.

"Getting the serious attention of law enforcement, prosecutors and the community in cases involving allegations of cruelty to animals is an essential step in protecting the community," the HSUS said in a news release.

"The connection between animal cruelty and human violence is well documented. Studies show a correlation between animal cruelty and all manner of other crimes, from narcotics and firearms violations to battery and sexual assault," the organization said.

?Shooting these three magnificent wild horses was an act of vicious animal cruelty, resulting in a young horse being left alone and motherless,? said Scott Beckstead, the HSUS? Oregon senior state director.

?We share the public?s outrage over these killings, and applaud the Crook County sheriff for aggressively investigating this case,? Beckstead said.

The HSUS Animal Cruelty Campaign raises public awareness and educates communities about the connection between animal cruelty and human violence while providing a variety of resources to law enforcement agencies, social work professionals, educators, legislators and families. The HSUS offers rewards in animal cruelty cases across the country and works to strengthen laws against animal cruelty.