meticulous search. they're scouring the very bottom of this lake looking for items that were missing from the franconia ho farooque home. the -- farook home. the hard drive was missing from inside the home. they're trying to find electronic evidence that helps build a case, helps them understand the picture here, the reason why in lake is so important to them. there was a report that two the killers were here on the day of the massacre. >> 14 people, of course, killed in the san bernardino attack. now the u.s. is keeping a close eye on how terrorist are getting their weapons. our jim sciutto got exclusive access to america's own rocket program. he saw their collection of dangerous foreign weapons. it's a stash they say might come in handy as they try to stay a step ahead of isis. >> reporter: a passenger plane headed from the netherlands to malaysia suddenly falls from the sky. malaysia airlines flight mh-17