WESTWOOD — Police say a woman told investigators that she accidentally hit the gas pedal instead of the brake in a crash that killed a 6-year-old boy and injured his father in Massachusetts.Anne Marie McInnis, of Westwood, pleaded not guilty on Tuesday to charges including motor vehicle homicide, assault and battery with a dangerous weapon and negligent operation.Court documents show the 20-year-old told detectives that she didn't see Edward "Eddie" Thomson or his father Robert in the November crash.