The long-running and notorious case of the Israeli private detectives accused of trying to carry out industrial espionage using specially-crafted Trojans has reached a conclusion of sorts – three members of the agency have been put behind bars.

According to reports from the country, Asaf Zlotovsky, Haim Zissman and Ron Barhoum, have been sent to prison for 19 months, 18 months and 9 months respectively, while the CEO of the Modi'in Ezrahi detective agency received a heavy fine and ten months on parole.

The case was underreported when it came to light three years ago, but deserves a place as one of the most revealing in recent security history for the way it alerted the world to the ease with which targeted Trojans could be used to steal sensitive information from unprotected companies.

The Trojans in question were created by an Israeli couple based in London, Michael and Ruth Haephrati – jailed for their part in the case in 2006 - who sold the software to the detective agency which in turn offered them to Israeli companies to spy on their business rivals.

The story was a classic Internet data theft sting. The Trojans were mostly mailed to named targets on CDs under the ruse of being business proposals. Once innocently opened, the software infected PCs and servers in an attempt to hunt for certain kinds of document, which were then emailed to FTP servers elsewhere on the Internet.

The amount of information stolen by the Trojans remains unknown, but reports at the time of the 2005 arrests mentioned the recovery of "tens of thousands" of documents from the servers, stripped from a wide range of companies, including an importer of Volkswagen and Audi cars, a large Israeli PR agency, and a television company.

Extraordinarily, the case would not have come to light had it not been for a mistake made by the creator of the Trojan, Michael Haephrati, who used the program in a private capacity to infect the PC of his estranged father-in-law, writer Amnon Jacont.

The software stole chapters of a book being worked on by Jacont, posting them to websites without his knowledge, presumably to annoy him. Jacont discovered the theft, reporting his suspicions to sceptical police, who then examined his PC, discovering the rogue program.

"It's understandable that firms would want information on what their business rivals are planning to do, and try to seek a competitive advantage over them. What isn't acceptable is to hire firms that will use illegal methods, such as computer spyware, to gather that information," said Graham Cluley of Sophos.

In fact, the case deserves credit for causing a marked tightening of security at large companies around the globe, who were quietly shocked at the simple way critical information was removed from servers without the victims even being aware. The chances of anyone at a large company falling for such a ruse are nowadays slim.

Anecdotally, security was tightened at many Fortune 100 companies, with encryption run over central document stores. The world had cause to thank an Israeli author and his insistence that police examine his PC for that insight.