FRAMINGHAM, Mass. — State police are investigating a pair of early morning fatal accidents.Authorities say a man walking on Interstate 495 north in Haverhill was struck by a vehicle at about 1:25 a.m. Friday.The victim was identified as 24-year-old Nicholas Nadeau, of Kingston, N.H.One man is dead and a woman is facing motor vehicle homicide and drunken driving charges in connection with a fiery two-car crash on Route 140 in New Bedford at about 2 a.m.