I agree with the observations that the shooter seems young - between 17-25, possibly military trained, and possibly trans-gendered. Their appears to be a limp in their gait - like a hip injury on the left side. Also one video appears that the right foot is inwardly rotated -pigeon toed, so possibly an injury on the right foot/ankle that causes an extended stride on the left. The gait has both masculine and feminine traits. I also see what appears to be very defined pectoral muscles and/or breast tissue. The shooter is wearing a hat with a hood over it. It almost appears in the video like a hijab, even though the actual items are western clothing. Some of the stills taken from the video appear very feminine in posture, but some of the gestures with the flip phone are more masculine. I took one still from the video that looks like a female figure with narrow waist, breast tissue, wider hips. It's confusing. Someone mentioned maybe trained in another country's military, and I wondered about that too. Maybe a recent Military discharge due to injury?