CSI: Mommy Edition

The crime scene:
    Three cupcakes hiding in the microwave, black icing missing

The clues:
    1.  The stool was pulled up to the counter.
    2.  The counter, the microwave, and the stool were covered in tiny black handprints.  Main suspect was questioned and told us that they were daddy's handprints.
    3.  The main suspect has a mysterious black substance all over his face. 
    4.  On day 2 of the investigation, the suspect filled his diaper with poop that was a lovely shade of tealish blue.  It looked like playdough.

Russ was booked and charged. 

Case closed.