The Bild newspaper said the perpetrator broke into the 51-year-old investment manager's second home in Storkow, in the eastern state of Brandenburg, on Friday evening.
After allegedly firing a warning shot at the ceiling, the kidnapper demanded €1 million. The man's wife was forced to tie up her husband and tape his mouth and eyes shut.
Before fleeing with the businessman in tow, he warned the man's wife not to call the cops. “If this demand is not met, he warned the woman that he would maim her husband by shooting him and then take her young son,” a police statement read.
Police said the kidnapper threw the man into a nearby lake, where the 51-year-old was made to hold onto a boat while he was pulled through the water.
He was then put in a rowboat, which ferried him to a reed island. Once there, police said he was given dry clothing.
The man's wife notified the authorities, who launched a secret search for the man. Up to 300 officers were on duty around the clock, with support coming from Berlin and the states of Mecklenburg-Western Pomerania and Saxony-Anhalt.
“The life and health of the victim was the top priority,” a police spokesman said.
On Sunday, the man successfully escaped by fleeing on foot, after two days during which he was bound and gagged. The victim came across another man, who called emergency services.
The 51-year-old was suffering from hypothermia, but otherwise did not sustain any injuries.