Car stalled while reversing. I tried to restart and could not get the car to crank. Jump was useless (radio, lights, etc. were working fine) so I had the car towed to my mechanic. They tried to start it the next day but it was a no-go. They tried it again the following day and it fired right up and has been starting fine since then.

Since the accessories/radio/lights were fine, I can rule out the alternator so I think it is either the clutch-pedal switch, the starter, or something with with the security system right?