As Ida Madison has said, this case will only be solved by "getting that one person who knows something to come forward."

If you have information that you think might help solve the case, no matter how trivial, please contact the proper authorities.

If someone you know has such information, encourage them to contact the proper authorities.

Inform family and friends about this case.  (If need be, direct them to this website.)  In turn, encourage them to tell others.

Pray for resolution and closure in this matter.
___________________________________________________________________________________________________________________________________________________________________________________________________________