A 7-year-old girl with signs of serious abuse fell out of a 6th-story window in the Gravesend houses Wednesday night. View Full Caption DNAInfo/Trevor Kapp

CONEY ISLAND — A 7-year-old girl with signs of serious abuse — including heroin in her system, rope marks and evidence of sexual abuse — plunged out of the window of her relatives' apartment Wednesday night, less than two hours after cops found her wandering the streets alone and brought her back to her family, law enforcement sources said.

The girl, who lives in Florida but was in Brooklyn visiting her stepmother's relatives, fell from a sixth-floor apartment in the Gravesend Houses at 7:43 p.m. Wednesday, sources said.

The girl was rushed to Lutheran Hospital, where doctors found signs of sexual abuse, rope marks on her hands and wrists, and so much heroin and methadone in her system that investigators believe they were administered via injection, the police sources added.

A family member leaving the apartment Friday declined to comment, but said: "She's doing okay."

"I want to get up. I want to get up. I want to get up," the badly-injured girl told witness Regina Speller, 51, as she lay struggling on the grass outside the building after the plunge, "I want to go home ... (to) Florida."

Speller added that the girl "kept trying to get up. I laid on top of her and just started praying. I was talking to her, trying to keep her calm. I asked her what was wrong, and she told me she wanted to go home," said Speller.

"She wasn't crying. She was just moaning. There was no blood. She was opening and closing her eyes," said Deloris Johnson, 65, who lives in the building.

Johnson said she asked the girl's caretakers what happened, and was told, "'I don't know. I just left her 10 minutes ago in the room."

The window to the apartment where the girl was staying had no window guard on it, sources said.

Before she fell from the window, the girl was found by neighbors wandering the streets.

Jennifer Smith, who lives near the girl's relatives, said she called police shortly after 5 p.m. when a family friend informed her that a young girl had knocked on his door.

"The girl kept saying, 'get someone to take me to the airport,'" said Smith, 38.

The girl — who wore black jelly sandals and carried a Mickey Mouse purse — seemed "alert and well behaved" and said she was staying in the apartment for the summer.

Smith "can't believe" that the girl tumbled from a window approximately 90 minutes after police returned her home, she said.

"I just want to give her a hug," she said.

Cops are investigating how the drugs got into her system, sources said. No one had been charged as of Friday. The girl and her 1-year-old brother was taken into custody by the city's Administration for Children's Services after a family court hearing Friday, officials said.

It could not be immediately determined whether the girl's family had any history of child abuse allegations or previous contact with the city's Administration for Children's Services or the NYPD.

Officers brought the girl back to the sixth-floor apartment and interviewed a 19-year-old girlfriend of the child's father, who told them that the girl had left the apartment in a huff.

The girl's father, who cops reached by phone in Florida, told them that the little girl had been angry lately because they were considering sending her to live in Haiti, sources said.

The officers determined that there was no evidence of wrongdoing and decided to leave the child at the home, but had to race back 90 minutes later when the girl plummeted out the window, sources said.

A spokesman for ACS said the agency was investigating an incident at that location.

No one had been taken into custody or arrested on Friday, sources said.

"They're good people, very good people. They're well-spoken, respectful. They always give you a kiss on the cheek. They're nice people," said neighbor Ernell Gomez.

Ben Fractenberg and Victoria Bekiempis contributed reporting.