Kid getting interviewed at the moment stated he heard an explosion first.
(Now I know i’ve heard they used gas or smoke first, never heard this)
Mom of kid said daughter said exit door by screen opened and someone threw something into the theatre (smoke, gas?). Within five minutes of the movie starting! Movie theatre has a lot of explaining to do on the exit door not being locked from outside. They need to quiz employees.
I’ve never been in a theater that had the exits locked. That would be a fire hazard. And people need to have free access to the $5.00 popcorn and $4.00 sodas.