A 1-month-old Queens girl was not mauled to death by a pit bull puppy inside the family’s housing project home — but died of unknown causes before the tiny puppy wound up biting her, the city medical examiner revealed Wednesday.

Police initially believed the tragic tot had been killed by the six-week-old  pup while her parents slept in their apartment at Queensbridge Houses public housing complex early Tuesday morning.

However, the New York City Office of the Medical Examiner said the dog bit off a “substantial portion” of her tiny face only after she had already died.

“The cause and manner of death are pending further study following the examination today,” a spokesperson for the office said in an email. “But we can confirm this is not a death from a dog mauling. The injuries inflicted by the dog were postmortem.”

The spokesperson said the cause of death is “pending further study to include a full pediatric workup.”

Cops made the gruesome discovery after the baby’s mother called 911 shortly after 6:30 a.m. Tuesday after finding her daughter mauled by the dog – initially believed to be what killed her. 

Neighbors reported hearing screams from the sixth-floor apartment before cops and EMS arrived at the scene. 

The mother allegedly told cops that the girl had been sleeping between her parents in bed when the couple woke up to find their dog, a pit bull-German Shepherd puppy, gnawing on the baby’s face. 

The baby, who was born on April 13, was pronounced dead at the scene.

Images of the beautiful baby show her napping at the hospital and in what appears to be the family’s home weeks before her tragic death.

Other photos show the dog — a tiny pup — at a city animal shelter. 

One neighbor recalled discussing the pup with the mother two days earlier.

“I told her, ‘That dog needs to be on a leash,'” building resident Shanel Nroville told The Post. “She said, ‘No, this dog don’t bite.’ I said, ‘All dogs bite.'”

Police are still investigating the incident and no charges have been filed in the case.