Lieutenant Hammertree was a Rebel operative during the Galactic Civil War. He was involved in gathering information regarding the recovery of Han Solo when Solo had been frozen in carbonite and taken by the bounty hunter Boba Fett. Hammertree discovered that another bounty hunter had been in league with Fett, but had been cut out of the reward when Fett left Cloud City. He brought this information to the attention of the Rebel leadership, but was killed by unknown causes soon afterward.