Joe Biden also reportedly targeted by serial bomber -- and the device may be still in mail system

Former Vice President Joe Biden may also have been targeted with a suspicious package, MSNBC reported Wednesday.

WNBC chief investigative reporter and NBC News contributing correspondent Jonathan Dienst joined "All In with Chris Hayes" with the latest on the still-developing story.

"Law enforcement officials we've spoken to say there is a concern a seventh package is out there, addressed to former Vice President Joe Biden and that it is being looked at," Dienst noted. "And that they think the address was wrong on that package and it's being sent back, perhaps to Debbie Wasserman Schultz's office in Florida."

Other packages included a Wasserman Schultz office as the return address.

"The search is underway for that potential package, there's information from the postal service that it's out there, they're trying to find it to see if, if that package is, in fact, linked to all the others," Dienst added.

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