PHOENIX (AP) — A Phoenix man has pleaded not guilty to first-degree murder stemming from the death of his girlfriend's 3-year-old daughter.
18-year-old Martwane Mackey pleaded not guilty to the murder charge and four counts of child abuse in Maricopa County Superior Court on Monday.
Phoenix police say that Mackey called 911 around 2 a.m. on June 25 and said that 3-year-old Tyshea Austin wasn't breathing.
When police arrived, they saw bite marks and injuries to her head and torso, and said that she appeared to have been dead for "some time."
Investigators found similar injuries to her 1-year-old sister.
Police say that Mackey admitted to abusing the girls but denied causing Tyshea's death. He said the girl had a breathing problem earlier that day, and that he bit and hit her to revive her.