Lahee and her mother were visiting friends at the apartment complex. Lahee, who did not know how to swim, was playing around the pool and accidentally fell in while trying to retrieve a ball, according to Menlo Park police spokeswoman Nicole Acker.
Her friend, who also did not know how to swim, went for help because the adults had stepped away for a moment. "It was an unfortunate accident," Ms. Acker said. "Our condolences go out to the family."
The accident happened around 5 p.m. Fire crews and police officers responded and found the girl near the pool, unconscious and not breathing, police said.
Medical personnel administered CPR in an attempt to resuscitate her, and took her to Stanford Medical Center, where medical staff continued CPR.
Despite these efforts, the girl was pronounced dead by the attending physician, police said.