An Indian-origin man in the East Midlands town of Leicester has been found guilty of blackmailing and taking part in a plot to frighten people into giving up thousands of pounds.
Jorawar "Jerry" Singh Khella, 29, was found guilty of blackmail, while his sister, Kamaljit Khella, 30, was convicted of perverting the course of justice, by giving him and another man, Scott Steve Lansdowne, 36, a false alibi.
The brother and sister will be sentenced at the Leicester Crown Court on September 7, reports from Leicester said.
At an earlier hearing, Lansdowne pleaded guilty to two counts of blackmail.
In the first incident on December 1 last year, the victim opened his door to Khella and Lansdowne, and was told that if he did not give them 4,000 pounds they would harm him and his family.
The victim asked for more time to find the money and Khella gave him a week. The victim then contacted the police.
The following day, a second victim, a local businessman, was also approached. Lansdowne pleaded guilty to demanding 13,000 pounds from the second man and threatening to seriously harm him if he did not pay up. Khella and his sister were also charged with this offence but were both found not guilty during trial.