Deer In The Headlights Look

[rbmartin]

Rule 8 Section 4 Art 2
(m) Any runner is out when he passes an unobstructed preceding runner before such runner is out (including awarded bases);...

If, as MD Longhorn stated, the trailing runner did not entirely pass the preceding runner that's one thing but if the trailing runner actually touches home while the lead runner has peeled off and is high fiving his teammates (before he has reached home plate), in my opinion you have no choice but to call the trailing runner out. What you do with the lead runner would be subject to appeal I guess.