<Tr> <Td> Rioters, residents of Newark, NJ </Td> <Td> Newark Police Department New Jersey National Guard </Td> </Tr> <Tr> <Th_colspan="2"> Casualties </Th> </Tr> <Tr> <Th> Death (s) </Th> <Td> 26 </Td> </Tr> <Tr> <Th> Injuries </Th> <Td> 727 </Td> </Tr>

Which of these was one main cause of the riots in newark new jersey and detroit michigan