The defendants said they had invited their financial adviser for a holiday
Four German pensioners have been found guilty of kidnapping the financial adviser they blamed for US property investments that went awry.
The court found that the four, aged 61 to 80, abducted James Amburn and tried to force him to refund 2.5m euros (£2.25m; $3.4m) in lost investments.
They took him from his home in western Germany and drove him 450km (280 miles) to southern Bavaria.
He was freed after hiding a message to call police in a fax to his Swiss bank.
The defendants had argued that they had invited Mr Amburn for a short holiday in upper Bavaria.
But the judge in Traunstein, Bavaria, ruled that it was a "spectacular case of self-justice" and that in Germany, people could not take the law into their own hands.
They were found guilty of offences ranging from kidnapping to grievous bodily harm.
The ringleader of the group, 74-year-old retired architect Roland Kaspar, was sentenced to six years in prison.
His accomplice, a 61-year-old businessman, was sentenced to four years. Two women, one of them Kaspar's 80-year-old wife, received suspended sentences.
The trial of another suspect, aged 67, has been postponed because he has health problems.
When the group's attempts to recover their money in the courts failed, they kidnapped Mr Amburn from his home in Speyer, Rhineland-Palatinate, in western Germany last June.
They tied him up with tape and gagged him, put him in a box in the boot of a car and drove him to Bavaria.
Along the way, they beat him up, breaking two ribs when he tried to flee during a stop.
They finally locked him in a well-prepared basement of a house close to the Chiemsee lake in Bavaria.
He was then forced to sign papers promising to refund the money the pensioners had lost in the US property crash.
But Mr Amburn managed to insert a message to call police in a fax sent to his Swiss bank. The bank then raised the alarm with German police, who stormed the lakeside house.