A source told SOFREP and thearmsguide.com that when Dallas SWAT made entry after the detonation of the explosive device, they encountered a Saiga AK-74 style semiautomatic rifle on the floor among the rubble. The weapon reportedly had a 30 round magazine, single point sling, Magpul folding stock, and a rail system with a red dot sight.
This photo is reported to be the actual rifle used taken after the explosive device went off.
The Saiga AK-74 is a semiautomatic version of the venerable AK-47. The AK-74 fires a smaller 5.45 X 39 cartridge more like that of the AR-15. Saiga is a Russian commercial company which imports rifles into the United States. The Saiga is at the more expensive end of AK style rifles.