Investigation into Nancy Guthrie's disappearance: what to know

Nancy Guthrie, 84, was reported missing from her Tucson home after last being seen Jan. 31; the FBI and Pima County investigators have released surveillance footage and collected evidence for laboratory analysis.

Nancy Guthrie, 84, has been missing from her Tucson home since Jan. 31 and was reported the following day. Authorities reported blood on her front porch and have expressed concern about her need for daily medication. The FBI released surveillance footage showing a masked person near the home and has called that person a suspect. Investigators have collected DNA and other items from the property and are sending evidence to a forensic lab for testing. Known details: - Last seen and reported: Nancy Guthrie was last seen on Jan. 31 and was reported missing the next day. - Suspect footage: The FBI released video of a masked person near Guthrie's front door and described that person as a suspect. - Evidence and testing: Investigators collected DNA not belonging to Guthrie or close contacts and submitted items, including gloves, for laboratory analysis. - Investigation actions: The Pima County Sheriff's Office and the FBI are coordinating the probe, have conducted searches and a court-authorized search was carried out; a person detained for questioning was later released. Summary: Investigators are continuing forensic testing and coordinating between local and federal agencies while the family has made public appeals. Undetermined at this time.