The latest death occurred at a hospital in Delaware.
Earlier this morning, hospital officials in Hershey, Pennsylvania, had announced the fourth death.
A hospital spokeswoman said the fourth victim was a seven-year-old girl who died about 4:30 this morning.
Spokeswoman Amy Buehler Stranges says the girl's parents were with her when she was taken off life support.
The girl died shortly after.
A six-year-old girl remains in critical condition and a 13-year-old girl is in serious condition at Penn State Children's.
Their names are not being released.
Three girls, ages eight, ten and 12, were flown to The Children's Hospital of Philadelphia, where a spokeswoman says they underwent surgery but remain in critical condition today.
The gunman killed himself.