I was watching CourtTV the other night with an episode about a guy that 50+ years ago robbed two couples (4 people) at a "lovers lane" area, forcing them to strip, raped one of the girls and then stole their car. As he was driving away from the scene he ran a stop sign and two hiway patrolmen pulled him over (not knowing what else he had done). He shot and killed both officers with his .22 revolver (one through the windshield on the officer's passenger side), but the driving officer, before he died, shot several rounds at the fleeing car with his .38 Special revolver.
They found the car abandoned with a few bullet holes in the back windshield and trunk, with one of the officer's rounds penetrating through the trunk, then through both the back and front seats. They checked at the hospitals for any gunshot wound submissions, but came up empty handed. They were also able to only get two partial thumb prints off the steering wheel, but weren't able to peg the print to any suspects.
It wasn't until almost 5 decades later when the niece of the guy reported to the police that she had heard her uncle mention the incident while drinking one night. Using new technology to "meld" the partial prints together and enhance them, they were able to verify that the print indeed matched her uncle and brought him in. Even though he had become a respected businessman in the community he settled in, and was 70+ years old, they found him guilty and sentenced him to life for the crimes. As well, he still harbored the scar on his back from that one officer's bullet that made it through the trunk and two car seats.
50 years ago cars were built of MUCH more solid and durable material than today for the most part, and suspect that the .38 Special rounds were probably just lead round-nose (though they didn't give details on that if I'm not mistaken). Therefore, aside from the skills of the shooter, I think many more factors than just bullet type, caliber and grains, or even what material it passes through, play a role in the path a bullet does or doesn't take. Personally, I believe that some are even guided, or mis-guided, by the help of guardian angles (but that's my own personal speculation and won't change, so please no debates or flames).
It may have taken over 50 years to bring him to justice, but at least in the end the officer got his BG!