Crank but no start

Cranks but does not start. Car stalled on highway while my wife was driving it. It was towed home. I started it without trouble three hours later when arriving at home from my work and drove it around the block without problems. I shut it off and then about half hour later tried to start it again. It cranked but would not start. It has not been able to start since then; just cranks fine but no start.
Check engine light on when key in auxiliary/power position. When cranking, tachometer remains at zero and does not move at all. Tried a plug wire with a screwdriver inserted and brought close to a ground while cranking and no spark.

How likely is this due to failure of the crankshaft position sensor? Might do further tests but extremely difficult because of tight, inaccessible locations of fuel rail, injectors, coil, Schrader valve, fuel pump, etc.