A reward is growing for information that leads police to an ATV rider who struck and killed a dog in Danbury.  The O'Rourke family initially said there would be a $500 reward, but neighbors and others have contributed through a GoFundMe page called Justice for Dusty.  In two days, 79 people have donated more than $5,700.  The 4-year-old husky-lab mix was killed Wednesday when an ATV rider lost control and hit her in the family's Jackson Drive yard.   Family members have said they understand accidents happen, but that the driver should not have left and should take responsibility.