Authorities pulled key surveillance video in Nancy Guthrie investigation days after initial attempts failed.

Those frightening images of a masked man on Nancy Guthrie’s porch could provide valuable clues to investigators.

Plus, in this week’s Installer: a new Mario Tennis, Sony’s great new buds, a wild time-travel movie, and much more.

The images show a person wearing gloves, a mask and a backpack appearing to tamper with the camera at Guthrie's front door. "We believe she is still alive," Savannah Guthrie said.

Understand how this artificial intelligence is revolutionizing the concept of what an autonomous agent can do (and what risks ...