The Hermit from the Northern Pond

In the 1980s, vacationers at Maine bases began to notice oddities: food disappeared, sometimes personal belongings. It seemed that they were being quietly robbed by an invisible man. People whispered about a ghost, about a mysterious tramp, but no one could figure out who was hiding in the woods of the Northern Pond.
Who is this man? Why did he leave civilization? And how did he manage to live in the forest for almost three decades?