CHANDLER, Ariz. -- Police are asking for the public's help as they investigate a Chandler man's death.Police said Robert Lopez, 49, sustained a severe brain injury after being involved in a fight on or around March 17, possibly in the area of Chicago and Dakota streets in Chandler.Lopez waited several days before seeking medical care, according to Chandler police Sgt. Joe Favazzo. He died Sunday and injuries he sustained in the fight may have contributed to his death. Silent Witness is offering a cash reward of up to $1,000 for information that leads to an arrest or indictment. Anyone with information about this case is asked to call Silent Witness at 480-WITNESS or the Chandler Police Department at 480-782-4130. Callers may remain anonymous.