ricky chiles iii , 27 , shot himself on thursday as police closed in on him .
police had warrant on wednesday for his arrest in connection to shootings .
chiles iii killed himself with single gun shot while at illinois motel .
rasheed chiles , 15 , was shot in the shoulder and died after two-year-old brother damani terry was run over by van after darting into street sunday .
gunman shot dead the driver of the van , 40-year-old archie brown jr , in a milwaukee neighborhood in a revenge shooting , police said .
brown was a father of four daughters , including a six-month-old girl .