The search is ongoing for 84-year-old Nancy Guthrie, the mother of "Today" show host Savannah Guthrie, who investigators say appears to have been kidnapped from her Tucson, Arizona, home in the early hours of Sunday, Feb. 1.
The FBI has released photos and videos of an armed person in a mask in front of her home, appearing to tamper with a security camera.
Anyone with information is urged to call 911 or the Pima County Sheriff's Department at 520-351-4900.
Click here for the detailed timeline of the investigation into Nancy Guthrie's disappearance.
A delivery driver who said he was detained by investigators in the Nancy Guthrie disappearance claimed in an interview that law enforcement officers had been following him.
The man, who only wanted to be identified as Carlos, said he was driving his Nissan Rogue on Tuesday evening in Rio Rico, Arizona, about 50 miles south of Tucson, when he noticed he was being trailed by a law enforcement vehicle.
"They were following me," Carlos told ABC Phoenix affiliate station KNXV. "And once I saw they were following me, I pulled over. They didn't even have to [make] a traffic stop. I got out of the car and they arrested me as soon as I got out of the car."
Carlos said he was not immediately told why he was being detained. But when an FBI agent and a Santa Cruz County deputy sheriff arrived at the scene, "They told me I was being detained for kidnapping."
"And I asked them, kidnapping of who?" said Carlos, adding that he was told of Nancy Guthrie.
He said that after being detained for several hours and having his vehicle thoroughly searched, he was released.
"Deputies detained a subject during a traffic stop south of Tucson," the Pima County Sheriff's Office said in a statement, confirming the man was "questioned in connection to the Nancy Guthrie investigation."
A woman who described herself as Carlos' mother-in-law told KNXV that investigators, armed with a search warrant, swarmed her home on Tuesday night, claiming they got a tip that Nancy Guthrie, the mother of "Today" show host Savannah Guthrie, was inside her house.
"I told them, 'You can go in and search my house,'" the woman said. "There's nobody there."
Investigators are not ruling out the possibility that more than one person may have been involved in Nancy Guthrie's abduction, the Pima County Sheriff's Department said Friday.
The sheriff's department said it also continues to seek information to help identify the man captured on Nancy Guthrie's doorbell video, and that investigators are reviewing surveillance video submitted by her neighbors.
A lawyer representing a convicted felon said his client and his client’s mother were briefly detained as part of the Nancy Guthrie investigation.
Luke Daley, 37, and his mother, who is 77, were detained and had their house searched on Feb. 13, according to his lawyer, Chris Scileppi. Their home is about 2 miles from Guthrie’s.
Chris Scileppi confirmed Daley -- who has served time in state prison on drug-related charge -- was the target of the operation by the FBI and Pima County Sheriff’s Department but reiterated neither Daley nor his mother were arrested and said they have no link to Guthrie.
“Like the entire Tucson community, both Mr. Daley and his mother are hopeful that Nancy will be returned to her family unharmed,” Scileppi said in a statement.
Daley was the second person detained for questioning and released after a deliveryman who identified himself as Carlos was stopped earlier in the investigation. ABC News has previously reported investigators are leaning away from both men as possible suspects.
-ABC News’ Aaron Katersky
The rewards for information leading to Nancy Guthrie or her captor now total more than $200,000 following an anonymous donation on Wednesday, according to the Pima County Sheriff's Department.
An anonymous donation of $100,000 to 88-CRIME increased the program's reward to $102,500, the sheriff's department said. That's in addition to the FBI's $100,000 reward.
The FBI has reached out to Mexican authorities to make them aware of Nancy Guthrie’s disappearance, law enforcement sources told ABC News.
There is no evidence she was taken across the border, but it’s an avenue investigators are exploring given the proximity to Tucson, Arizona, the sources said.
-ABC News’ Aaron Katersky and Luke Barr
A delivery driver who said he was detained by investigators in the Nancy Guthrie disappearance claimed in an interview that law enforcement officers had been following him.
The man, who only wanted to be identified as Carlos, said he was driving his Nissan Rogue on Tuesday evening in Rio Rico, Arizona, about 50 miles south of Tucson, when he noticed he was being trailed by a law enforcement vehicle.
"They were following me," Carlos told ABC Phoenix affiliate station KNXV. "And once I saw they were following me, I pulled over. They didn't even have to [make] a traffic stop. I got out of the car and they arrested me as soon as I got out of the car."
Carlos said he was not immediately told why he was being detained. But when an FBI agent and a Santa Cruz County deputy sheriff arrived at the scene, "They told me I was being detained for kidnapping."
"And I asked them, kidnapping of who?" said Carlos, adding that he was told of Nancy Guthrie.
He said that after being detained for several hours and having his vehicle thoroughly searched, he was released.
"Deputies detained a subject during a traffic stop south of Tucson," the Pima County Sheriff's Office said in a statement, confirming the man was "questioned in connection to the Nancy Guthrie investigation."
A woman who described herself as Carlos' mother-in-law told KNXV that investigators, armed with a search warrant, swarmed her home on Tuesday night, claiming they got a tip that Nancy Guthrie, the mother of "Today" show host Savannah Guthrie, was inside her house.
"I told them, 'You can go in and search my house,'" the woman said. "There's nobody there."
