freddie gray , 27 , died sunday a week after his arrest at the gilmor homes .
four officers arrested him for a violation that has not been disclosed .
was dragged during the arrest and witness said his legs ` looked broke '
he was loaded into a transport van and put in restraints on way to station .
30 minutes later ambulance was called to station to take him to the hospital .
died , was resuscitated , stayed in coma and underwent extensive surgery .
justice league nyc organized rallies at station where gray was taken .
baltimore mayor has promised thorough investigation and ` real ' answers .