Unabomber Theodore Kaczynski kept shoes with smaller soles attached to the bottom in his reclusive cabin to evade authorities chasing him, according to evidence released 10 years after his capture.

FBI agents were questioning students at the prestigious Yale University law school today, after an explosive device went off in an empty classroom.

Three letters contaminated with anthrax all were dated September 11, the same day as the terrorist attacks on New York and Washington, and contained anti-American and anti-Israel messages, US officials said.