ONE HALF of the bridge is in Mexico, the other half is in the United States. See the 20 foot comment you ignorant SOB.
As for your "shell casing" argument ...
The official, who agreed to discuss the matter only if not quoted by name, said the video also shows what seem to be four Mexican law enforcement officers driving to the edge of the dry but muddy bed of the Rio Grande, walking across to the U.S. side, picking up an undetermined object and returning to Mexico near the area where the boy's body was. Like their U.S. counterparts, Mexican law officers are not authorized to cross the border without permission.
Don't know about you, but that sounds like they went into the US took the shell casing, went back across the border, and planted false evidence next to the body.
And before you get on about how wide this "bridge is" ... One suspected illegal immigrant was detained on the levee on the U.S. side, the FBI said in a statement. Another Border Patrol agent arrived on the concrete bank where the now-dry, 33-feet (10-meter) wide Rio Grande is, and detained a second suspect. Other suspects ran back into Mexico and began throwing rocks, the FBI said.
And if you look at the photo where the body is, he isn't "right near the EDGE where it starts, he is surrounded by concrete, so he is at best, more in the center. Hence my "20 foot" comment.