Authorities are looking for clues in the death of a newborn girl who was found Sunday floating in a pond in a suburban Virginia town about 30 miles west of Washington, D.C.

The Loudoun County Sheriff's office said a resident of Sterling, Va., reported seeing a deceased baby in a pond behind a cul-de-sac shortly before noon Sunday. 

Authorities responded to the scene and declared the infant dead. They said the birth did not appear to have occurred in a hospital and that the mother may need medical attention.

Authorities spent hours Sunday knocking on doors in the neighborhood adjacent to the pond, near Awsley Court and Steed Place in Sterling, hoping to find the mother, NBCWashington.com reported.

Neighbors told NBC some local residents fish in the pond, and it is also a popular hangout for teenagers.

Seven children who were reported missing Saturday from their Fresno, Calif., home were found with their estranged father Thursday, police said.

"The children were unharmed and were all in good spirits," a Fresno Police Department spokesman said early Friday.

Police said they had left the kids in the custody of their father, Xa Yang, in Sacramento, while an investigation is conducted. Sacramento is about 170 miles north of Fresno.

On Thursday, police said Yang had previously not had contact with the children for more than three years.

They lived with their mother and stepfather, who left them alone Saturday evening and went grocery shopping, police said. When the couple returned to their apartment complex, all seven children were gone, as were their belongings.

Police said then that there were no serious concerns about the children's safety.

The FBI Task Force for Violent Crimes Against Children was called in to assist, however, and its agents found Yang and the four boys and three girls, ages 12, 11, 10, 8, 7, 6 and 5.

The children were thought all along to have been with their father, police said, but they did not know where he lived. 

The Fresno police spokesman said he did not have information about the parents' custodial rights or why the children were left with their father instead of being returned to their mother.

"Fresno and Sacramento PD will investigate further to determine if a crime was committed," he added.

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Cops believe estranged father took 7 missing California kids