Rescuers descended into a deep cave to rescue a trapped dog -- then they found a bear

Firefighters encountered an unexpected challenge while rescuing a dog trapped in a Tennessee cave: A black bear was also there.

The dog, Charlie, spent three days trapped nearly 40 feet deep in an "extremely narrow cave shaft" on English Mountain in eastern Tennessee, according to a Facebook post from the Waldens Creek Volunteer Fire Department.

A rescue team consisting of "rope rescue technicians" from several fire departments set off on the mission to free Charlie on Tuesday, the Facebook post says. The team hiked to the mouth of the cave, where firefighter Tori Downing and captain Jon Lanier descended into the cave.

"Things took a turn when Firefighter Downing rounded a corner and found a bear sleeping five feet below her and the trapped hunting dog farther in the cave system," reads the Facebook post.

Charlie's unwitting companion was a 2-year-old black bear weighing an estimated 200 pounds, according to the Waldens Creek Volunteer Fire Department.

The rescue team left the cave and set up trail cameras to track when the bear left the cave, the Facebook post says.

On Wednesday, they determined that the bear "had left the cave and not returned."