BrainScratch: Martha Jean Lambert - Case Closed?

David confesses to his mother:
https://youtu.be/sHfrsnnzqzc

Sources:
http://www.sjso.org/?page_id=5365
https://en.wikipedia.org/wiki/St._Augustine,_Florida
http://staugustine.com/stories/112804/new_2730440.shtml#.WeitQWhSxhG
http://www.truecrimereport.com/2010/01/martha_jean_lamberts_brother_c.php
http://staugustine.com/news/local-news/2010-01-02/cold-case-solved-after-24-years
http://staugustine.com/stories/121901/new_354624.shtml#.Weiwc2hSxhE
http://abcnews.go.com/US/missing-girl-cold-case-solved-cops/story?id=9465748
http://staugustine.com/news/local-news/2010-01-07/detectives-stand-cold-case-confession
https://www.google.com/maps/@29.8875236,-81.3544766,3a,39.5y,352.19h,85.36t/data=!3m6!1e1!3m4!1sse1INm2s6f9RX4aIQvbsQw!2e0!7i13312!8i6656

More Info:
http://www.charleyproject.org/cases/l/lambert_martha.html
https://charleyross.wordpress.com/tag/martha-jean-lambert/
http://www.lifedaily.com/story/missing-cold-case-of-martha-jean-lambert-finally-solved-after-25-years/
https://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=83505435