Nancy Guthrie poses with daughter Savannah Guthrie in an undated photograph. Courtesy NBC/Today/Handout via Reuters

The FBI has been in touch with the Mexican government and Mexican law enforcement regarding the disappearance of Nancy Guthrie, the mother of "Today" show co-host Savannah Guthrie, law enforcement sources told CBS News.

Authorities believe Nancy Guthrie, 84, was forcibly taken from her Tucson, Arizona, home in the middle of the night before she was reported missing Feb. 1. Pima County Sheriff Chris Nanos told CBS News partner network BBC News this week that he believes Guthrie was targeted in the apparent abduction.

The FBI maintains dedicated border liaison agents stationed along the border who work directly with their Mexican law enforcement counterparts on these kinds of situations.

The FBI's legal attaché office in Mexico City serves as the bridge between FBI headquarters, the U.S. Embassy and Mexico's federal attorney general's office.

One source told CBS News the FBI suboffice most relevant to the Guthrie case is in Hermosillo, Sonora, the Mexican state that shares a border with Arizona. Tucson is about 60 miles from the Nogales crossing.

The U.S. State Department has issued a Level 3 travel advisory for Sonora, which is one level beneath its most severe advisory. The State Department urges Americans to reconsider travel to the area, noting a risk of violence from terrorist groups, cartels, gangs and criminal organizations.

Hermosillo is roughly 170 miles into Mexico on the other side of the border. When something happens in this geographic corridor, that is the suboffice that gets the call.

Nanos has said there's no indication Guthrie was taken into Mexico, but that doesn't necessarily mean that an investigation in the area has not been launched.

Attorney General of the State of Sonora Gustavo Rómulo Salas Chávez said Thursday, "We have no information to suggest that this person is in Mexican territory, specifically in Sonora."

Carlos Flores, the commissioner general of Mexico's Criminal Investigation Agency, said Thursday, "The FBI informed us that they currently have no leads to suggest that this person could be in Mexico."

One source said border protocols are already in place for situations like this, whether or not there is a confirmed lead.

Meanwhile, the local organization Madres Buscadoras De Sonora (Searching Mothers of Sonora) told CBS News they were contacted by a Guthrie family member and asked to help in the search. The organization, which is well known in Sonora, posted a message on social media asking for information about Guthrie's whereabouts.

A reward from the 88-CRIME tipline was increased on Wednesday to $102,500 — thanks to a $100,000 anonymous donation, the organization said — for information leading to the arrest of the person or persons involved in Guthrie's disappearance. That reward is in addition to a $100,000 reward the FBI is offering.

According to Nanos, investigators have not ruled out that an accomplice aided the suspected kidnapper seen in doorbell camera video outside Nancy Guthrie's home the night of her disappearance.

The video recovered from Guthrie's Google Nest doorbell camera, which was shared by the FBI last week, is the only footage that Google has been able to recover from the cameras at Guthrie's home, according to the Pima County Sheriff's Department. There are additional cameras from the property that engineers are still working through as they try to recover usable video. Investigators are hopeful that tech companies working on the videos will uncover more.

Savannah Guthrie, her two siblings and their spouses were all cleared as suspects in the case, the sheriff's department announced Monday as the high-profile investigation entered its third week.

Nanos told BBC News the Guthrie family has cooperated with investigators.

"We really put them through the wringer," Nanos said. "We take their cars, we take their houses, we take their phones, all this stuff — and we're not taking it. They're giving it to us voluntarily. They have been 100% cooperative with us through everything we've asked. They are victims. They are not suspects."

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