In Jack Reacher, based off of the Lee Child novel, One Shot, one of the key threads Reacher pulls on that convinces him of Barr's innocence is that shooting from the parking garage was an incredibly bad tactical position with the sun in the wrong direction, a lateral field of fire, and ample opportunity to leave evidence compared to firing from a van on a nearby bridge where the sun would be behind the van, the targets would be stacked up in a narrow horizontal space, the brass would be caught inside the van, and there would be an easy egress by pulling back into traffic. A point is made that shooting from the garage would require an inhumanly perfect performance, including the one "miss" to provide an undamaged bullet to be traced as evidence. Both methods of shooting are shown at least twice in the film. The original novel, as best I remember, and can figure out by quickly browsing through an electronic copy from the local library, does not have a second shooting location. There are some physical evidence traces in the garage, but it's also indicated that one of the officers involved in the investigation planted evidence to point to Barr.
So, ultimately, the question is, was the shooting done from the garage, or from the bridge?