It really reminds me of a loss of perspective and the "tunnel vision" coming on a bit quick and in a larger context than in a gunfight.
The officers lost perspective when it comes to the sheer number of pickups out there, much less the ones that actually match the actual description of the suspect's. They got lost in the tunnel vision convincing themselves that they had the suspect despite all of the peripheral evidence that indicated other wise.
Indeed it was small version of "mob psychology" playing out. Their individual fears fed off each other and therefore fed their mechanism for quelling their fear. That mechanism was gunfire.
Just a hunch.