lawyers for the parents of michael brown announced wednesday night that they planned to file a civil lawsuit against the city of ferguson .
attorneys for the family said in a statement wednesday night that the wrongful death lawsuit would be filed thursday .
brown was unarmed when he was fatally shot by a white police officer in a st. louis suburb in august 2014 .
the shooting led to sometimes-violent protests and spawned a national ` black lives matter ' movement calling for changes in how police deal with minorities .