Renee Radziwon, 36, of Portland, died in the Saturday night attack at WildCat Haven Sanctuary in suburban Sherwood, Deputy Mark Nikolai of the Clackamas County Sheriff's Office said Sunday.
Nickolai told CBS News affiliate KOIN in Portland that Radizwon had been attacked by a cougar. Sheriff's Robert Wurpes said the animal was locked in a cage following the attack.
Radizwon was believed to have been alone with the animal in its enclosure, although the sanctuary said its handbook specifies that two qualified staff members be present during the lock-out of a "dangerous" animal.
"We are devastated by this loss. Not only was she one of our most dedicated staff members, we thought of her as family. We send our most heartfelt prayers to those she has left behind," said Cheryl Tuller, executive director of the sanctuary.
Tuller added that Radziwon had been working at the sanctuary as the head keeper for eight years and was a certified tech.
Jim Caliva, a Wildcat Haven Sanctuary board member, told The Oregonian that Radziwon was an experienced worker who had a good rapport with the animals.
"Her relationship with the cats was amazing," Caliva told the paper. "She knew exactly what she was doing, but apparently there was a mistake. I don't know what it could be."
Caliva said Radziwon worked with all the cats at the sanctuary.
"They knew her and walked up to the fence," he told The Oregonian. "She was one of the best people I've ever met."
Its website describes the facility as a "last hope" for wildcats that have been abandoned or abused, including bobcats, cougars, lynx and tigers.
As of this summer, there were 67 animals at the sanctuary, KOIN reported. Last year the sanctuary rescued two Bengal tigers, Nora and Katie, from their life in Ohio.
In less than a year, they move into a home 10 times larger -- 82 acres -- about 40 miles south, KOIN reported.
The facility is not open to the public, but does provide on-site tours to donors.