As the search for Nancy Guthrie continues into its seventh week, Rick Kastigar, the former boss of Pima County Sheriff Chris Nanos, has shared a grim theory on what he believes happened to the missing 84-year-old.

Speaking to NewsNation’s Brian Entin on the latest edition of Brian Entin Investigates, Kastigar said he thinks multiple people were involved in Nancy’s abduction and that it’s likely she was taken to Mexico in hopes of getting her the medication she needed to keep her alive.

Nancy, the mother of Today co-host Savannah Guthrie, has been missing since January 31, when police believe she was abducted from her home in Tucson, Arizona. Since then, investigators have released doorbell camera footage of a masked suspect and shared a description of the potential abductor.

Kastigar said it would be in the kidnappers’ interests to keep Nancy alive so they could bargain with the family, most likely for money. Therefore, he thinks it’s reasonable to assume they would have taken Nancy to Mexico to address any potential medical issues.

“What would prevent an individual who had planned this out—to the level that I think he did—from going into Mexico and harboring her someplace in Mexico where, theoretically, they could deal with her medical issues,” the former police chief told Entin.

However, Kasitgar added that he believes Nancy “died somehow, while that plan may have been attempted.”

“And I believe that negated their opportunity to get what they wanted from the family. A lot of us think it’s money—and that very well may be,” he continued.

Kasitgar also pointed to pleas from Savannah and the Guthrie family, which state they want Nancy brought home, but don’t specify “alive.”

“My theory is that she’s passed,” he stated. “My theory is that they have nothing—they being the perpetrators—really have nothing with which to bargain any further. and what they may have done with her, I don’t know.”

Previous reports noted that Nancy’s pacemaker stopped syncing with her Apple Watch on February 1. Nanos also revealed Nancy had limited mobility and required daily medication for high blood pressure and heart issues.

Read the latest entertainment news on TV Insider.