2011 Hyundai sonata not cranking

I have a 2011 Hyundai sonata I was driving it and
the car stalled which is a little bit of smoke on the
belt side I will had it towed to a mechanic thinking
it was the starter he put a brand new starter on and
it started drove the car down the street and then
it's stalled they came and put another battery on
and it started back up again I put my old battery
back on and it stopped so I bought a brand new
battery put the brand new battery in and then it still
did not work brought the car home took it to
another mechanic who said it was the key
reprogrammed a new key and then he told me it
was the engine was locked I checked the alternator
had it tested and it is a bad new battery but the
battery is still draining I do not know what could be
wrong with my car need help