Harvey Levin and Mark Geragos Connect Dots in Nancy Guthrie Kidnapping

Nancy Guthrie's kidnapper has eluded authorities for 2 weeks, but the ransom note TMZ received is of intense interest to the FBI, and Harvey Levin and Mark Geragos both agree ... it may be the key to cracking the case.

H&M's latest "2 Angry Men" podcast makes it clear ... the FBI is laser focused on that ransom letter, for reasons we cannot publicly discuss. They are also interested in the man who has sent TMZ 3 demand emails asking for bitcoin in return for giving up the kidnapper's name. BTW ... the man says the kidnapper is the "main individual" -- meaning there's more than one person involved.

Law enforcement's dramatic move Friday night apparently did not yield results, but there are a number of clues, including unknown DNA found in Nancy's house. It's currently being analyzed.

TMZ has identified the backpack and the jacket the kidnapper was wearing ... we believe it to be an Athletic Works Fusion Knit Jacket -- law enforcement has not confirmed.  Both items are sold at Walmart, so they may help law enforcement track down the kidnapper.