According to Turkish Deputy PM, "plane was hit by a heat-seeking l@ser-guided missile" Heat seeking or l@ser guided? Syria has l@ser-guided SAMs? (like Bofors RBS-70?)
I suspect the solution is rather straightforward.
The politician mis-spoke the briefing given to him by a member of the military.
IR homing with a laser fuse seems the simplest, most logical, conclusion based on the brief, although I rather suspect it was a Pantsi(y)r S-1:
Newly-supplied Russian Pantsyr-1 anti-air missile used to down Turkish warplane
In addition the first report stated the RF-4 was at 100m, not 100'.
I have also read that the jet was downed 13km of the coast, not that it was 13km under the water.