The FBI has been in touch with the Mexican government and Mexican law enforcement regarding the disappearance of Nancy Guthrie, law enforcement sources told CBS News.

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.

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

Pima County Sheriff Chris 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.

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.