(Covers information from Anderson's universe)
Ma was the matriarch leading a group of survivors. As a possible means to lure in unsuspecting survivors, Ma and her sons would play a looped S.O.S. message pleading for help and detailing wounded survivors at a station called KLKB.
As luck would have it, Alice responded to the S.O.S. and intended to help them before realizing she'd walked into a trap. Ma and her sons mocked her and her son, Eddie tried to rape Alice, despite her warning not to touch her. She kicked Eddie, snapping his neck with a kick. Ma ordered her boys to send Alice to the dogs.
Alice defeated a few of the undead dogs and managed to escape the pit with the surviving dogs behind her. Jumping out of danger, Alice allowed the dogs to kill Ma and her boys.