Do you mean the steering had locked all the way to one side - or the WHEELS were not turning? Was the ignition lock OFF and the steering wheel was free to turn as it wanted.
You didn't say what year Wrangler - it makes a difference.
Second Gear would make no difference.
It's rare but possible that the steering column turned all the way to one side - and stayed there. You could also have front suspension wear prolems which could contribute to the cause.
Dealers typically are clueless to towing issues.
If your tires were fully worn, there should have been SMOKE and NOISE sufficient to alert you to the problem. I doubt it was immediate.