AITA for my friend getting suspended

One day we were going on trip with my school we were getting ready to go in the yard of the school and my friend was playing in his phone (here in Greece they are not allowed and if caught you get one day suspension) then a teacher caughts him and takes my friend to the principal where he tells her he was trying to contact his mother who was sick (actually was playing clash royale) then the principal decides to investigate it and the next day the principal takes me to question whether my friend was actually trying to contact his mother or just wants to get away the suspension i tell her that he was playing clash royale (without knowing my friend had told the principal he wanted to contact his mother ) then after that he gets the one day suspension he is angry with me for not covering for him.So i want to know if i am the asshole because i don't think i am