48 Hours Sneak Peek: The final days of JJ and Tylee

REXBURG, Idaho (KIFI/KIDK) - It's still one of the most talked-about missing person's cases in the country.

Two sweet-faced siblings, 16-year-old Tylee Ryan and 7-year-old JJ Vallow vanished without a trace from their home in Rexburg Idaho.

For six months, their mother, Lori Vallow, and her new husband Chad Daybell famously refused to answer the question on everyone’s mind: where are the children?

Sadly, we now know the answer - their remains were found in Chad Daybell’s back yard last June.

For the first time, we’re learning how investigators pieced together the final days of JJ and Tylee as I sat down with CBS News Correspondent Jonathan Vigliotti Friday to preview an all-new "48 Hours" Saturday, October 3 at 9 p.m. on KIDK TV 3.

You can view our coverage of the Daybell-Vallow case here.

Watch 48 Hours: "Sneak peek: The Final Days of JJ and Tylee"