Lieutenant Governor Timothy P. Murray has written to political supporters telling them that he has been subjected to “false rumors and wild speculation’’ since he crashed his state-owned car last November while driving in excess of 100 miles per hour. “I understand that when a public figure is in any kind of accident people want to know how it happened,’’ Murray wrote. “Unfortunately, false rumors and wild speculation can result even when the details of the matter have been released to the public.’’