According to survivors, Long was dressed in all-black, wearing a baseball cap, sunglasses and a mask covering the bottom part of his face. He walked up to the entrance at 11.20pm and shot the bouncer before making his way into the venue.
He then shot a young female cashier before throwing smoke grenades onto the dance floor and letting off rounds into the crowd.
Survivors described how he carried the attack out with careful precision and said he had 'perfect form' when shooting.