Kathmandu (CNN) -- Aubrey Sacco from Colorado went trekking alone in Nepal, against her parents' advice, and disappeared. That was three years ago. There has been no trace of her despite many searches.
A breakthrough in her case came this week when Nepalese police arrested two men who hail from the region where she vanished. "We assume that she has been murdered," police said Saturday.
The 16-year-old and the 22-year-old suspects are from Langtang, about 60 miles north of Kathmandu. They are in custody on suspicion of the alleged crime, chief Anurag Kumar Duwedi said.
Sacco's family had been worried there would be no serious investigation despite their offer of a $25,000 reward for any information on her.
Her father, Paul Sacco, a brother and one of their friends flew to Nepal to scour mountain trails after she vanished in April 2010. They had no luck, and what they heard from locals in the beginning discouraged them.
They told them that if they did know something about the case, they would not share it with authorities.
Sacco's parents have made three trips each to Nepal to search together with military and police for any sign of her, her mother Connie said.
They have hired private detectives to help on the ground over the past three years, but the trail went cold.
"No leads, no evidence of any sort," she said.
Sacco went on the trek in the Langtang National Park after graduating from college. She was 23 at the time.
She was living up to her motto, "glitter the world," on a five-month trip through South Asia, her family says.
The artist and musician first taught yoga to vacationers in Sri Lanka. Later, she went to India, studying yoga and volunteering to help schoolchildren with art and music.
She preferred staying with villagers as opposed to high-end places, Connie Sacco said. She looked forward to volunteering in Nepal.
CNN's Jason Hanna contributed to this report