FBI conducts extensive search near home of Nancy Guthrie

The FBI conducted an extensive search near the Arizona home of Nancy Guthrie today. It's the latest development in an investigation that has picked up momentum since authorities released videos of a masked armed man at her door the morning she disappeared. The 84-year-old was abducted back on February 1st. Alex Stone has more on today's search and a man questioned by law enforcement overnight. FBI agents today conducting what they say is an extensive search along multiple roads in the Catalina Foothills area of Tucson as they investigate the suspected abduction of Nancy Guthrie. A delivery driver detained by the Pima County Sheriff's Department and the FBI overnight for questioning in connection with Guthrie's disappearance is out of custody and free. The man who says his name is Carlos tells ABC affiliate KNXV he was pulled over about an hour south of Tucson and was detained for six hours. The detectives got here. It was the FBI agent in Santa Cruz County and they told me I was being detained for kidnapping. And I asked, kidnapping of who? And they told me this lady. I don't know her name. And um... Nancy Guthrie? Yeah, that's her. He says as a delivery driver he may have delivered packages to Guthrie's neighborhood. Law enforcement sources tell ABC News he had been on the radar of law enforcement before the public release of the doorbell video. The sources say the FBI identified him through his cell phone usage and traffic data. He was questioned for several hours and was released without any charges. Carlos' mother-in-law says she was not involved in the kidnapping. the home they served. They only said that they gave a tip that she was in my house and I told them you can go in and search the house. There's nobody there. Today the case remains focused on this video recovered from Nancy Guthrie's front doorbell camera. Investigators hoping somebody recognizes this person's walk, his eyes, mouth, or what he's wearing. Enough to offer a tip. Investigators have been back at the home of Nancy's daughter Annie going to neighbors asking questions but Nancy Guthrie's whereabouts remain unknown. In Los Angeles, Alex Stone, Channel 6 Action News.