Extremists Online Discussed Blowing Up Planes Weeks Before Northwest Flight 253 Attempt

JERUSALEM, Jan. 4, 2010 — -- 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.

The company, Terrogence, is run by former intelligence agents who for the last four years have monitored and occasionally participated anonymously in extremist Internet sites.

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."