A psychologist testified that the FBI used advanced psychological techniques to lure a teenage terrorism suspect into agreeing to a plan that would have killed thousands.

Elizabeth Cauffman, a defense witness in the trial of Mohamed Mohamud, testified Tuesday that undercover FBI agents rewarded risky behavior and used social pressure to convince Mohamud to attempt to detonate a weapon of mass destruction at Portland's 2010 Christmas tree-lighting.

The bomb was a fake supplied by the FBI.