(CNN) -- A 4-day-old died after being attacked by his family's pit bull terrier Sunday evening at his home in Jacksonville, Florida, according to John Harrell, a spokesman with the Florida's Department of Children and Family.
The infant's father told CNN affiliate WJXT he and the baby's mother only left the child alone for a few seconds when the attack occurred.
Jacksonville Sheriff's office along with Florida's child welfare agency are investigating the incident as a child death.
The state agency will determine if the child was unsupervised and for how long.
"Our investigation will reveal if the incident was abuse, neglect or an accident," said the DCF spokesman.
The state agency's report will show if the the dog had any history of aggression. The father told WJXT the dog had never shown aggression toward any member of the family. DCF reminded parents how dangerous it is for pets to be around small children.
"It's a very tragic case and our sympathy goes out to everyone who knew the child, " said Harrell.
The final report on the incident is expected to take weeks to complete.
WJXT reported the dog was euthanized.