I'm sure it was the runway they were cleared for. Often these threads and the reports from the msm are full of speculation from aviation buffs and private pilots who while well intentioned are just out of there element.
I normally stay away from them but when someone starts speculating people are impaired and acting as if using a wrong runway is as easy as turning the wrong way down a one way street. It's just too much.
It would be surprising if they did take off from the wrong runway. Someone, whether in the tower or in the cockpit should've seen the error. 8/26 is only actually used during daylight and VFR conditions.
Considering where the wreckage is located though, it certainly sounds like the pilots took-off from 8/26. For the pilots to have taken off from the correct runway (4/22), it would've had to veer hard right shortly after takeoff to end up in that area.