How do you think these officers would feel, if they found out later, that the driver they were encouraged to pull over was the prime suspect in a quadruple murder----and they were not told about that glaring fact?
I would be livid if I were them. There is a reason that felony stops have specific protocol. You wait for back up, you have weapons pointed and you have them step out of vehicle, show their waistbands and walk back slowly with arms raised.
You would never walk up, alone, no weapon ready, to the car window if you knew the driver was a fleeing murder suspect.