The desperate search for Savannah Guthrie’s mom continues in Arizona, with authorities entering the fourth day of a widening investigation into the disappearance of Nancy Guthrie, 84. The Pima County Sheriff’s Department announced Wednesday morning that investigators have yet to identify a suspect and are working “around the clock” alongside federal officials and the Guthrie family.

 “Detectives continue to speak with anyone who may have had contact with Mrs. Guthrie,” the department said in a statement.

Nancy Guthrie was reported missing Sunday afternoon from her home just outside Tucson, after she failed to attend church services that morning. Sheriff Chris Nanos of Pima County told NBC News that the missing person case remains the department’s highest priority. The situation has drawn national attention, as “TODAY” show co-anchor Savannah Guthrie remains in Arizona to assist with the search and support her family.

Guthrie was last seen around 9:45 p.m. Saturday, when relatives dropped her off at her home. Officials believe she may have been taken during the night and have not ruled out the possibility of an abduction. 

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The FBI has become actively involved, working alongside nearly 100 detectives from the sheriff’s office. President Donald Trump also said Tuesday that he would dedicate additional federal resources to assist the ongoing investigation.

Despite receiving “hundreds of leads,” investigators have yet to uncover any credible evidence suggesting the disappearance was targeted. 

Sheriff Nanos described the situation as “extremely challenging,” noting that a technical malfunction with Guthrie’s home security cameras has limited access to overnight footage. Moreover, attempts to gather video surveillance from nearby properties have been hampered by poor lighting and dense landscaping.

According to family members, Savannah Guthrie's Mom has limited mobility and is currently without critical daily medication. Authorities emphasized that she has no cognitive impairments and is considered mentally sharp. “We have nothing else to go on but the belief that she is here, she’s present, she’s alive, and we want to save her,” Nanos said.

Recent unverified reports suggested that ransom notes referencing Guthrie were sent to media outlets, though no law enforcement agencies have substantiated these claims. The Pima County Sheriff’s Office confirmed it is “aware” of such reports and is “taking all tips and leads very seriously,” sharing all information with FBI investigators.

Evidence collected so far includes Nancy Guthrie’s cellphone, her car, and several DNA samples from her home. However, officials stated that none of the tests have pointed to a suspect or person of interest.

As the search presses forward, NBC Sports confirmed that Savannah Guthrie will remain in Arizona and not travel to Italy as planned for coverage of the Paris Olympics. “Our hearts are with her and the entire Guthrie family as the search continues for their mother,” NBC said in a statement.

For continued updates on the case, visit NBCNews.com.