Michael and Ruth Haephrati, the brains behind the Trojan horse high-tech industrial spying program, landed Monday evening in Ben Gurion airport as part of Britain's extradition of the two to Israel.
The couple is set to stand trial in Israel after dropping an appeal against their extradition in London.
After landing in the airport, the two were taken for interrogation in the fraud division of the Tel Aviv district police department.
The Haephratis left Israel several years ago and have since been living in Britain and Germany. At Israel's request, British police arrested the couple in May 2005, a few days before their Israeli counterparts released details of the affair to the media on May 29.
The couple is suspected of having developed and sold the Trojan horse hi-tech spy program to three private investigation companies in Israel - Modi'in Ezrahi, Zvi Krochmal and Philosof-Balali. The companies allegedly offered the program to industrial and commercial firms to spy on their competitors. It was installed in the victims' computer systems by way of an innocent-looking e-mail attachment.
Companies suspected of using the Trojan horse program included Meir Motors (Volvo-Honda) against Champion Motors (Volkswagen), water retailer Tami-4 against Mei Eden, Amdocs against a reporter for the Globes newspaper, Bezeq International against Zahav Lines and Home Center against Ace Hardware.
Several of the suspects in the case are currently standing trial in Tel Aviv District Court.
In November, the daily Yediot Aharonot quoted Haephrati as saying he had received 1,700 from Modi'in Ezrahi each time the private investigation company used his program.