It has been one month since Nancy Guthrie was first reported missing. The case has captivated the nation’s attention, but despite the constant spotlight on Tucson, Arizona, there are still far more questions than answers about what happened to the 84-year-old mother of “Today” anchor Savannah Guthrie.

Investigators have received tens of thousands of tips, and followed up on thousands of leads, but nothing appears to have panned out. Two people were briefly detained for questioning, but both were released within 24 hours, and law enforcement officials say neither man is considered a suspect.

The lack of a suspect, a gut wrenching video released by Savannah Guthrie on Tuesday acknowledging that her mother “may already be gone,” and news last week that the FBI was shifting its command post from Tucson to Phoenix may give the appearance that the case has gone cold.

“This is nowhere near a cold case,” Miller said. “They still have leads that are viable that they need to get to, including new leads that came in because of the strategy of holding back the big reward until the time it was needed to re-energize the lead bucket,” he noted, referring to the $1 million reward offered by the Guthrie family on Tuesday.

“There is still plenty of science that is out that hasn’t come back yet. There are still investigators working leads that they’re not finished with. If we’re having this conversation a year and a half from now, that would be a cold case, but right now, the current nature is pretty opaque, so we can’t say it has gone cold,” Miller noted.

Here are Miller’s three biggest questions as investigators head into this next phase of the case:

What is the fate of Nancy Guthrie?

It may seem obvious, but whether investigators have reason to believe Guthrie is still alive is key to determining how the rest of the case will proceed.

“The question of the fate of Nancy Guthrie is a central one because with a victim who is still alive, there is a certain sense of urgency with a life hanging in the balance that keeps things moving at a fast pace,” Miller said.

“With a victim who you either know or presume is likely ᴅᴇᴀᴅ, the investigation can slow down and in fact even become more meticulous. You have a lot more time to delve into time consuming lines of investigation that can be productive in the long term.”

Was this in fact a kidnapping for ransom?

The question of motive continues to plague investigators, and answering it remains every bit the priority.

“There’s always the possibility that this was some kind of planned home invasion that went completely sideways and was re-engineered into being a kidnap for ransom because the suspects’ opportunities had shifted,” Miller said. “The key denominator here is the blood outside the front door, which offers a strong suggestion that, whatever type of crime it started as, things began to go wrong very quickly.”