Extremist Internet forums discussed blowing up planes three weeks before the Detroit attempt -- and have also discussed ways of using deadly biological agents onboard planes.
A private Israeli intelligence company told ABC News Monday there was a surge of online discussions in extremist Islamic forums about blowing up planes three weeks before Umar Farouk Abdulmutallab's attempt to bring down Northwest Flight 253. The discussions recommended using "improvised detonation chain" devices, exactly like the one used onboard the Detroit-bound flight.
The company has also tracked specific -- and in its view -- credible plans to attack planes using deadly biological agents.
Three weeks ago company founder Gadi Aviran and colleagues noticed a surge in Internet traffic from well-known extremists talking about how to bring down planes using combinations of chemicals including PETN, the chemical used by Abdulmutallab on Christmas Day.
"These discussions were about the exact same technique used on the Detroit flight," he said. "There were very detailed instructions on how many grams of chemicals to use, so as to avoid detection. They also talked in great detail about what liquids should be used."
From those details and level of expertise displayed Aviran says he knew the threats were serious and sent a warning to his company's clients worldwide which include in his words, "Western governmental agencies."
At the same time he claims there have also been terrifying online exchanges about using aerosols filled with biological agents to attack planes.
Two individuals, both well-known members of extremist forums, according to Aviran, have been leading these discussions which include the use of Botulinum toxin. Botulinum is one of the deadliest substances known to mankind.
The two individuals have been participating in Islamic Internet forums for several years and are known to the intelligence gatherers at Terrogence.
"These are not kids talking about using biological agents to attack planes. These are two very sophisticated participants who are experts in chemical and biological agents."
According to Aviran, his company monitors 10 main extremist Web sites. The sites use sophisticated security and screening methods to prevent infiltration by Western spy agencies.
To gain access to restricted areas of online discussion takes time and patience. Passwords and user names have to be issued, and members are often barred when they are suspected of working for Western governments.
The sites allow Islamic extremists to share information about how to attack Western targets. Once an attack takes place there is often a surge of traffic about how to improve the method of attack.
Aviran claims extremists "are always looking for your Achilles heel. And when they find it, that's where you will be attacked. It's a very efficient and seasoned machine that works 24 hours a day, there's no union and no holiday."