123? Sorry. Couldn't resist.

It wasn't the original guy they thought. It was the builders son who had done the recent bombings. He found the old book on how to make his b*mb using the same ingredients and chemical makeup as the one 30 years prior. He thought dad still felt the same way from 30 years+ regarding anti-war and peace movement stuff.

Cisco was the undercover old FBI guy.

Hope it helps.