I just finished my second poly for a TS/SCI clearance for a government contractor.  The first time i failed.  The polygrapher claimed that everytime he asked me if i had committed a serious crime that the results appeared that i was withholding information.  Anywho, the whole process took about 3 hours.   

The second time I went, I didnt admit anything new (I am a clean guy) and the polygrapher did two sets of lifestyle questions, left the room, came back and said I no longer needed to be tested.  I asked if the results looked good, and she replied that if I wasn't lying, everything should be okay.  The whole second poly only took about 40-45 mins.   

Is this a good sign, or should I still be concerned??

Thanks!!

You should never ask, if you passed the poly.  I have
extensive experience with NSA, and can tell you that
a third poly is probably coming.  I made the same
mistake, when first starting out there, and they had
me come back.  If you don't get through their process,
good luck getting a TS/SCI elsewhere.  I was lucky,
and was able to get TS/SCI, with a different agency.
All the "mumbo jumbo",  just to work there, isn't worth
it (you'll be disappointed).