A reported lead in the disappearance of Nancy Guthrie has placed TMZ founder Harvey Levin at the center of an unusual standoff with federal investigators, after he disclosed that the FBI asked his organization to "stand down" while authorities pursued an anonymous source demanding one bitcoin in exchange for alleged evidence tied to the case.

Speaking in separate interviews over the weekend, Levin said he had been prepared to facilitate a cryptocurrency payment to an individual who repeatedly contacted TMZ claiming to possess information identifying Guthrie's alleged kidnappers and the location of a cellphone containing what the sender described as video from what may have been the missing Arizona woman's final day.

The claims add another layer of uncertainty to an investigation that has remained unsolved for nearly five months. Nancy Guthrie, 84, disappeared from her Tucson-area home on Jan. 31 and was reported missing the following day. Since then, the FBI and the Pima County Sheriff's Office have treated the case as an apparent abduction while pursuing thousands of tips but have publicly identified no suspects.

According to Levin, the anonymous email campaign began shortly after Guthrie disappeared and has continued intermittently from what he described as the same IP address. During an interview with CBS producer Anna Schecter, Levin said he eventually concluded the sender might warrant closer scrutiny.

"'A month ago, I called the FBI and I said, "Look, I just have this sense this guy might be real,"'" Levin said.

Levin explained that TMZ proposed documenting a controlled bitcoin payment-worth roughly $60,000-in coordination with law enforcement while tracking the cryptocurrency transaction in hopes of identifying the sender. He said federal investigators initially indicated they would respond quickly but communication later stalled.

"'I had made six calls and I felt they were ghosting us,'" Levin recalled.

According to Levin, the bureau later contacted him with a different request.

"'I did get a call back this week and they asked us to stand down, to not do the documentary,'" he said, adding that investigators told him they believed they were "making progress in terms of identifying this person" without TMZ transferring cryptocurrency.

The FBI has not publicly confirmed Levin's account of those conversations. Neither the bureau nor the Pima County Sheriff's Office has commented on the alleged bitcoin proposal or on whether investigators have identified the individual responsible for the emails. IBTimes UK could not independently verify Levin's description of the discussions.

In a separate interview with CNN's Michael Smerconish, Levin outlined what the anonymous correspondent allegedly claims to possess. According to Levin, the sender says a cellphone stored in a secure location contains "a 'short video of the main guy with Nancy on the day that was probably her last.'" The individual also allegedly promised to provide the phone's passcode and identify two purported kidnappers after receiving one bitcoin.

TMZ requested a still image from the alleged video to help authenticate the claim before any payment. Levin said the sender refused, arguing that releasing even a single frame could expose the source to the alleged kidnappers.

"'If you're asking me, how do I make sense of all of it? I'm having trouble,'" Levin told Smerconish.

He added: "'On the one hand, if they think this guy is just a j*** trying to scam money, why are they spending all this time... trying to figure out who this guy is? On the other hand, if he's legit, why didn't they pay the one Bitcoin he's asking, which is around $60,000, to lead them to the kidnappers, and possibly Nancy Guthrie?'"

The reported bitcoin demand is only one of several anonymous communications received during the investigation. Guthrie's family and media organizations have also received ransom-style notes allegedly originating from the same IP address. One message claimed Guthrie remained alive, while another asserted she had died after suffering a medical emergency and had been buried in a remote natural area. Authorities have not verified any of those claims or publicly linked them to a suspect.

Pima County Sheriff Chris Nanos has expressed skepticism regarding the communications. Speaking previously on local radio, Nanos suggested investigators could be dealing with "another one" of the false ransom-note schemes that have surfaced in other high-profile investigations.

The emotional toll on Guthrie's family has become increasingly visible as the search continues. During NBC's "Today" last week, Savannah Guthrie addressed the case while distancing herself from the network's editorial coverage.

"'I don't have any comment on this story and I'm not involved in our coverage, but I can't pretend I'm not here,'" she said.

She continued: "'We are in agony and we cannot be at peace. No matter how much I try to come out here every day and smile and find that joy, and I will, I promise I will, this is the moment to tell you we need your help, we're begging for your help, and I'm not going to miss that opportunity.'"

Nearly five months after Nancy Guthrie vanished, investigators continue to sort through thousands of leads while separating potentially valuable information from what law enforcement believes may be false claims. Levin's account suggests federal authorities consider the anonymous email campaign significant enough to investigate, even as officials have declined to publicly characterize the sender or reveal how the latest lead fits into the broader investigation.