Published: Apr 02, 2013 6:08 PM EDT
Updated: Apr 02, 2013 6:13 PM EDT

FORT MYERS, Fla.- Newly released discovery documents shed new light in the homicide invstigation of a Fort Myers toddler.

Police say Derrick Johnson shook and beat Brianna Addison, 2 while babysitting her earlier this year.  The child's mother, Shawna Hall, left Addison and her other children in her boyfriends care for more than ten hours.  The couple lived together in the Horizons Apartments off Summerlin Road.

Hall told investigators she checked on her children while they slept shortly after midnight on January 31st, but was called back to the home by Johnson after leaving for work.

In a recorded phone conversation with a 911 dispatcher Hall said, "My boyfriend just went in there to wake up my daughter and he called me back.  She will not wake up.  I was leaving and he called me back.  She will not wake up.  Her lips are blue.  She has like fluid coming out of her nose and her mouth.  I don't know what's wrong.  She will not wake up."

The dispatcher spent approximately seven minutes walking Hall through CPR before paramedics arrived on scene.  Addison was pronounced dead a short time later at Physicians Regional.

She died of blunt force trauma to the head, according to the medical examiner who noted the child's body was badly beaten, with a welt resembling a leather belt noted on her cheek.

In interviews with prosecutors, Shawna Hall and Hall's mother said Derrick Johnson never showed signs of phsyical abuse toward the girl.

However, Fort Myers police say the suspect admitted to throwing the girl in the air and letting her head hit a piece of furniture in the living room.

Johnson is charged with aggravated child abuse and manslaughter.