As the story goes, Mary was the mother of Juju, of the infamous Juju Road.  Once Juju was hung, Mary wanted to
have her revenge.  She lured off the owner that killed Juju's children, murdered them, and threw them over a bridge,
into the creek below but the original story was that Mary had vowed revenge for it and lured off the owners 2
smaller children, murdered them and threw them over an old bridge into a creek. Mary killed herself shortly after.

Today, it is said that on the anniversary of Juju's death, if you go to the bridge and call out Mary's name, you can
hear her moan and scream.

Thanks to Des for the info