Nancy Guthrie's Home Crawling With Police and K-9s, New Videos Show

Investigators descended on Nancy Guthrie's Arizona home Wednesday as they returned to the scene of the crime -- and new video shows them piecing together leads in the puzzling case.

Monica Garcia, a TV reporter for Tucson's KVOA-TV, posted video showing federal and local police investigators crawling all over the house -- noting they were wearing latex gloves and carrying out boxes of items.

One of the clips captures a Customs and Border Protection agent outside the home with a specially trained K-9 dog used by law enforcement to locate drugs, explosives, and missing persons.

In the midst of this, 'TODAY' anchor Savannah Guthrie released an emotional public plea Wednesday night to her mom's captors, asking for proof Nancy is still alive. Savannah said she's aware of an alleged ransom letter demanding payment in exchange for Nancy's release, and said the family is open to talking with her mom's alleged kidnappers.

Meanwhile, investigators also paid a visit Wednesday to the Tucson home of Savannah's sister, Annie Guthrie, and Annie's husband, Tommaso Cioni.

A federal agent was photographed carrying a bag over his shoulder with the contents believed to be a forensic device that accesses data from smartphones, SIM cards, and more.

The Cellebrite Universal Forensic Extraction Device can also retrieve encrypted data and deleted content.