marc wabafiyebazu , 15 , bragged to officials that he and jean , 17 , would go on raids together around canada .
the pair were ` buying $ 5,000 of marijuana ' when jean was shot dead .
marc may be charged with his brother 's murder under florida law .
details have emerged of their indulgent life driving mother 's bmw in miami .
their mother is roxanne dube , the recently appointed canadian consul general in miami .
they had driven to a house with friend joshua white , 17 , who also died .
gunfire erupted soon after they entered , marc was in the car at the time .
alleged dealer anthony rodriguez , 19 , was wounded . he was also arrested on charges of felony murder .