Lightning strikes in Colorado earlier this month killed two elk hunters who were caught in a storm, authorities concluded this week.

Andrew Porter and Ian Stasko, both 25, had been hunting in the Rio Grande national forest in southern Colorado the week of 11 September when they stopped making contact. After extensive search and rescue operations, crews came upon their bodies a week later.

Bridget Murphy, Porter’s fiancee, confirmed their cause of death in a social media post this week, writing that he was an “experienced outdoorsman, who was in the wrong spot at the wrong time”.

“It is OFFICIAL, that a lightning strike near them took them in an instant. They didn’t do anything wrong, they didn’t feel fear or pain,” Murphy wrote. “He was just trying to get back to the car as storms rolled in on Friday – September 12. It was out of everyone’s hands, and I am so grateful we found them so they can be at peace.”

A storm hit the area where Porter and Stasko were hunting and brought cold temperatures, strong winds and lightning.

The Conejo county coroner’s office told media on Tuesday that he performed the autopsies this week and found that lightning struck the pair as they stood under a large tree. Authorities initially reported their bodies had no clear injuries or signs of trauma and determining their cause of death was challenging, said Richard Martin, the county coroner.

The lightning left a few slight burns on their bodies, and likely killed them instantly, Martin told the Colorado Sun.

“That kind of death is just instant. It’s like you’re alive and now you’re not,” he said. “Just that quick. Split second.”

According to data from the National Weather Service, lightning causes two deaths and 12 injuries a year in Colorado.

Murphy, Porter’s fiancee, described him as “sensitive, strong, brave and carefree.

“He was so kind, attentive to me and our dog and he had so many dreams. He wanted to start a business, build our home, teach our kids to be maniac athletic hunting outdoors people, have a farm and grow old with me,” she wrote.

“I sure feel like a widow. I sure feel like my future is blank now. But what reassures me is that they were doing what they loved, without fear, well prepared and equipped and this is a bizarre horrific act of nature. It could’ve happened anywhere, to anyone.”