The Stuxnet virus that put back Iran's nuclear program by some years was planted by an Israeli backed terrorist group.
A member of the Mujahedeen-e-Khalq (MEK) used a corrupt memory stick, US intelligence officials said.
It is these same Israeli proxies who have been bumping off Iran's nuclear scientists, these sources said.
Vince Cannistraro, former head of the CIA's Counterterrorism unit, was quoted in IS Source as saying that the MEK is being used as the assassination arm of Israel's Mossad intelligence service.
The dissidents have a functioning, effective network inside Iran and they have access to officials in the nuclear program.
The MEK was founded in the 1970s, the group was stridently anti-Shah and allied itself with the dictatorship of Iraq's Saddam Hussein. It helped him kill domestic opponents and the massacre of Iraqi Shias and Kurds in the 1991 uprising.
In France, they conducted killings in Paris, including six or seven US Army sergeants. He added the French "were terrified of them."
A saboteur at the Natanz nuclear facility, who was a member of an Iranian dissident group, used a memory stick to infect the machines there. Once the memory stick was infected, the virus was able to infiltrate the network and take over the system. US officials said they believe the infection commenced when the user simply clicked on the associated icon in Windows. Several reports pointed out this was a direct application of one of the zero-day vulnerabilities Stuxnet used.