Nice. I really like the cartoony style you used, not just for the faces but for the entire environment. This looks like it could have originally been a short animation. The grainy effect makes everything look just a little bit more subdued, which works since it's at nighttime and makes everything just a little more realistic. Certain inconsistencies such as the finger or the cop's arm do take away from it but overall I really do like it. It's also cool that you added glasses to Benjamin Franklin - nice job.
Something that bothered me that goes beyond the basic mistakes and oversights is that the green colors are almost glowing. Hell, the bottom panel looks like I'm getting a codec call from Benjamin Franklin. You really could have toned it down to make it look more fitting. The lines that appear on the bill also should have been subdued a bit, because they really dominate the picture otherwise, more than an actual dollar bill does.
One last thing I'd like to say is that while there are some mistakes, there are some really great things that you went out of your way to add. The first that jumps out at me is the siren light on the second panel. The cop car is not even shown in any of the panels, yet you did a great job of implying details just by glow and shadow.