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CRIPPLE CREEK, Colo. — Some of Colorado’s more well-known paranormal investigators made their way to Cripple Creek this weekend to study the “unexplained.”

The group participated in the fourth annual Spirits of Colorado Paranormal Convention. The event featured ghost hunters, psychic mediums, UFO investigators and regular people who have an interest in the unknown.

Among the many who spoke was Chuck Zukowski, the self-proclaimed “UFO Nut.” Zukowski talked about animal mutilations in Colorado and highlighted a situation that happened in August 2014.

“This was the largest, most complicated animal mutilation I’ve ever done,” Zukowski said.

It took place about 13 miles northeast of Walsenburg. About eight cows died within a week and a half. Zukowski drove out to investigate it.

“I go in-depth with these investigations,” he said. “We learn as much as we can.”

The convention was held in the historic mining town of Cripple Creek, which is said to be haunted. Ghost hunters and psychic mediums brought attendees on tours around the Imperial Hotel and the St. Nicholas Hotel, which locals say house several ghosts.

About 200 people attended the event.