Nancy Guthrie, mother of Today show host Savannah Guthrie, disappeared from her Tucson-area home in Arizona. Law enforcement sealed a road near her house late Friday night. A convoy of sheriff and FBI vehicles, including forensics units, passed the roadblock about 2 miles from the home. The Pima County sheriff’s department confirmed the activity relates to the Guthrie case but could share no more at the FBI’s request. Nancy Guthrie, 84, was reported missing on February 1. Authorities found her blood on the front porch of her home. Ransom notes sent to news outlets raised hopes but two ransom deadlines have passed without any news. Officials are worried about Nancy’s health because she requires daily medication. She has a pacemaker and suffers from high blood pressure and heart problems, according to sheriff’s dispatcher audio on broadcastify.com. Investigators have reviewed surveillance videos, processed thousands of tips, and sent DNA and other samples for lab testing. The FBI has gathered more than 13,000 tips since the disappearance. The sheriff’s office received at least 18,000 calls. On Tuesday, authorities released brief video footage showing an armed, masked person at Nancy Guthrie’s doorstep on the night she vanished. The clips, less than a minute long in total, give police and the public a first look at a key suspect outside her home in the foothills near Tucson. Experts say this video may hold many crucial clues.