This is so sad.  It's surprising she lasted this long.  WLNS Channel 6 says that authorities are looking for anyone who might have any information about this dog and who might have mistreated her.  Animal Contro thinks she may be a Mastiff mix and weighs only 41.7 pounds.  A healthy female Mastiff should weigh 120-170 pounds.  If you have any information about her or her owners please contact Animal Control through their anonymous tip line at 676-8376 or ac_shelter@ingham.org.  There is a $500 award for information that leads to the conviction of the person responsible.