Grandparents Plead for Return of Hannah Anderson

This morning, more sightings and more concern about the fate of 16 year old Hannah Anderson in the hands of her alleged abductor James DiMaggio, CNN's Miguel Marquez reports.

There have been dozens of sightings of the dark blue Nissan Versa outside of California, with Amber alerts now lighting up much of the western US.  [Watch Above Video]

Investigators are saying DiMaggio may have built his own explosives, ditching his car and wiring it to explode.

"If you see this car, do not approach it, but call law enforcement," says Jan Caldwell, San Diego County Sheriff's Department.

This as the human toll is taking it's effect. Sara and Ralph Britt – mother and step father of Christina Anderson and grandparents to Hannah and Ethan- spoke exclusively to CNN.

Sara and Ralph Britt/Victims' Parents and grandparents
"Please let Hanna go," says Sara.

"Let her come back," says Ralph.

They believe that Hannah is alive. They hold out hope 8-year-old Ethan is alive as well, but they fear the worst.

Steve Moore, former FBI agent specializing in the investigation of violent crimes, adds his perspective on how police might know James DiMaggio has explosives:

"Likely, what you're going to do is try to figure out what he's done in the last few weeks, months, before this kidnapping. They may have found explosives or detritus of the explosives, at his house, or purchase records." [Watch Video Below]