Snowball
If Piazon has a case to answer he'll end up getting extradited, unless he does a runner to Brazil first, or locks himself in the Ecuadorian embassy.
For some bizarre reason the arrest warrant for Piazon is only "Ontario wide" not Canada-wide and means he can't be extradited
I would imagine, that the other guy is the main offender hence they are more eager to speak to him whilst they have grounds to believe that Piazon was party to the assault but not an active participant. As a result, until they have managed to speak to the main suspect he remains a person of interest. At this stage, it is not likely to be worth the cost of extradition but if after speaking to the main suspect they feel Piazon has a larger case to answer they will apply for a larger warrant and go from there.