On Friday night, police said Stephanie Williams got home from work at the usual time around 6 o'clock but investigators said her evening was not routine.
First responders were called to the home shortly before midnight where they found Williams' daughter, 21 month old Anayah, unresponsive.
She was rushed to Frederick Memorial Hospital where she later died.Police said the baby girl had visible bruises and marks on her little body.
By Saturday, police had charged Frankie Williams, the baby's father, with first degree child abuse resulting in death, first degree child abuse with severe physical injury and first degree assault. Investigators believe he caused the injuries that killed her.
"We're talking about a 21 month year old child who tragically died at the hand of her father," said Lt. Clark Pennington, Frederick Police Department.
WHAG first met Stephanie Williams on Sunday. She defended her husband, calling him a "good man" despite the allegations against him..
"My husband loved his daughter...Very much...And whatever was going through his mind i know it wasn't...He wasn't in his right mind when he was doing these things," said Stephanie Williams, victim's mother.
But by Monday, Williams herself was facing charges in the case. Investigators arrested her and charged her with first degree child abuse resulting in serious bodily injury.
"And we believe based on the totality of the situation and on past information that the mother did not care for the child properly when she became in charge and care of that child," said Pennington.
Police say they looked at the time frame when the baby was injured. They believe the victim's father caused the injuries and her mother was home and knew about the abuse and didn't seek immediate medical assistance.
"And based on all that situation and all of the circumstances basically the totality of the circumstances lead us to believe that the mother was complicit or at least she was involved in some way in not providing care to the child which results in first degree child abuse for her," said Pennington.
This is an ongoing investigation but police say they will take this case to a grand jury.
Both Stephanie and Frankie Williams are being held at the Frederick County Adult Detention Center.