Flowers told CNN affiliate KOMO-TV he thought about calling the police.
Then he buried the leg in the back yard of his home on the Nisqually Indian Reservation in western Washington.
"I'm 93 years old," he said. "I didn't want to have to go to the pen for something I didn't do."
On Saturday -- four days after the discovery -- his daughter, Cheryl Flowers, arrived. When he told her what happened, she said, "Dad, we have to call the police."
So on Sunday, the Thurston County sheriff's office put a tracking collar on Liberty and deployed five other search dogs along with 30 volunteers, Acting Lt. Ray Brady said.
Liberty didn't lead them to anything helpful. But the trained dogs found a skull, pelvis and a rib cage in nearby woods.
Authorities did not know whether the remains belonged to a man or woman.
Brady said the remains appeared to have been scattered by a wild animal. Flowers said the leg he buried -- which deputies dug up -- appeared undamaged from the knee down.
Thurston County Coroner Gary Warnock told KOMO-TV a pathologist will examine the remains.
By Dave Alsup and David Simpson with contribution from CNN's Jake Carpenter.