Also... if this is a big issue juggling it all together and having it make sense. It would be easy enough to do the whole thing in third person. I've read a few crime suspense books where they switch between different perspectives throughout the book. Actually the book "The DaVinci Code" (the one that was turned into a movie some years ago) does this, switching from the main character to different bad guys from chapter to chapter. It's all done in third person and no one is confused because usually the first paragraph of the new perspective tells you who's PoV it's from. Your first line could start "Rob was looking at the scene from his car." and the reader immediately knows that this part of the story is done from the PoV of Rob. Doing the same thing in first person would be very difficult because the same context clues can't be naturally written in.