Name is mud

If someone's name is mud they are in trouble, disgraced, or discredited.

The idiom's origin is said to refer to Samuel Alexander Mudd (December 20, 1833 – January 10, 1883) who was an American physician, imprisoned for conspiring with John Wilkes Booth in the assassination of U.S. President Abraham Lincoln. However, according to an online etymology dictionary, this phrase has its earliest known recorded instance in 1823, ten years before Mudd's birth, and is based on an obsolete sense of the word "mud" meaning "a stupid twaddling fellow".

Example: If she doesn't prove her innocence, her name will be mud.