The son of Eugene Kaspersky, co-founder and CEO of the antivirus company Kaspersky Lab, has been freed unharmed after apparently being held captive for four days last week.In a rescue operation on Friday by the Russian Federal Security Service (FSB), 20 year-old Ivan Kaspersky was reported by Russian news sources to have been discovered in a house outside Moscow with five people now accused of being behind the abduction.The ringleader of the gang has been named in the Russian press as being 61-year old Nikolai Savelyev, allegedly aided by his wife, son and two of his son's friends.The ransom demanded has been put at 3 million euros ($4.3 million), with the kidnappers traced as via mobile phone as an interin payment on the ransom was being arranged. No ransom was paid despite earlier and apparently deliberate disinformation from police that money had changed hands.Ivan Kaspersky had been kidnapped on his way to work at a company run by his mother and former Kaspersky Lab front-woman, Natalya Kaspersky.The exact circumstances surrounding the affair remain confused. Eugene Kaspersky attended the Infosecurity Show in London last week where he was scheduled to carry out interviews with journalists. He is said to have remained in London until Wednesday, the day after his son's abduction.Kaspersky is a wealthy man on the back of an empire that has made his company one of the biggest names in European software security. He is also a modest man who eschews the obvious trappings of wealth. His prominence would still have made him a target in a country notorious for kidnappings.