No One is to Blame

One of the twins pooped in the tub today and even though they alerted me to the fact, they both vehemently denied having done the deed.
I couldn't figure it out myself. 
Was it the one who scampered off to get dressed by himself? 
Or was it the one who lagged behind to make sure I cleaned up the mess?

song: No One is to Blame • artist: Howard Jones