DALLAS (CBSDFW.COM) – A North Texas mother, accused of failing to stop her boyfriend from abusing their three-year-old son, has been arrested.

Police continue to investigate the murder of three-year-old Josiah Garcia, but said their initial inquiries have revealed the little boy couldn’t count on his mother or father to protect him.

Josiah’s father, Christopher Garcia, is in jail – accused of beating the boy to death. And Tuesday Josiah’s mother, Catalina Garcia, was arrested for not stepping in to stop the pummeling.

Catalina Garcia was booked into the Dallas County Jail early Tuesday afternoon. The 21-year-old mother faces an injury to a child by omission charge, a first-degree felony.

Police sources say Catalina Garcia could have stopped her boyfriend from beating their son and failed to seek medical help for the boy, who slowly died from his injuries in their Oak Cliff apartment.

Last week, Christopher Garcia was charged with Capital Murder for allegedly punching little Josiah over problems with potty training.

Extended family members of the couple declined to comment on the arrests.

Christopher and Catalina Garcia have two other young children who are in the custody of Child Protective Services.