welcome back to "the lead." today, the investigation tracing the steps of the terrorist couple who dropped their baby off before murdering 14 people. right now a dive team is combing through a murky lake in san bernardino. they are looking for a hard drive or any evidence that would help explain how syed rizwan farook and his wife tashfeen malik killed those 14 people last week. did the couple work with a wider terror ring to plan their attack? did they take orders from a foreign group overseas? cnn justice correspondent pamela brown has been in touch with her sources. pamela, what's new in the investigation. >> we're learning, jim, that an fbi investigator is believed that before the shooting attack the killers visited that nearby park where divers are doing the painstaking job of searching the lake looking for items that the attackers may have thrown away. among the items the divers are a searching for is a computer hard drive that investigators believe the shooters removed from the home in an attempt to hide their