martyh

quote
"if he had done his job properly then possibly Hayley would not have been killed by him."

and possibly if her parents had done there job properly then hayley would have been in the house at that time of night

An accident is a specific, identifiable, unexpected, unusual and unintended external action which occurs in a particular time and place, without apparent or deliberate cause but with marked effects. It implies a generally negative probabilistic outcome which may have been avoided or prevented had circumstances leading up to the accident been recognized, and acted upon, prior to its occurrence
here's the dictionary definition of accident i believe all the criteria have been met in this case