St. Louis County police dispatcher Paul Jackson said Alisa Maier was found late Tuesday in the St. Louis suburb of Fenton, after police received a call about a child wandering around at a car wash.
Witnesses at the car wash noticed the girl around 9:45 p.m. Tuesday after a car with a loud muffler got their attention, FBI spokeswoman Rebecca Wu said early Wednesday. The car was described as a black or dark brown four-door vehicle with missing wheel covers on the driver's side, Wu said.
An officer who arrived at the scene said Alisa looked tired, Wu said. She was taken to a hospital and has been reunited with her family.
Police continue to search for the man suspected of abducting the girl from the front yard of her Louisiana, Mo., home.
She and her 5-year-old brother were playing about 8 p.m. Monday night. The boy told police a man he did not know, driving a beaten-up, dark four-door sedan, pulled up and ordered his sister to get in before driving away.
Police had only a vague description of the abductor - possibly a white male with dark hair in his late teens or early 20s.
Louisiana, a town of about 4,000 residents 80 miles north of St. Louis, has a Mississippi River bridge. The family's home is a short distance from Route 79, a highway along the river that runs from Hannibal to the St. Louis vicinity.
Alisa's disappearance affected everyone in town, right up to the chief of police, reports CBS newswoman Tara Mergener, with an emotional Rich Hughes telling reporters, "I don't personally know Alisa. I have children the same age, and my heart goes out to Roy, and Alisa's parents."
Roy Harrison, Alisa's grandfather, added that she's " a really good girl. Always smiling. Happy-go-lucky."
Neighbors told CBS News of a chaotic scene Monday night, with Alisa's grief-stricken mother sobbing in the street and then heading off in her own vehicle in pursuit of her child.
They said Alisa -- wearing a white t-shirt and blue jean shorts -- and her brother were alone outside only minutes as her parents went into the kitchen to prepare dinner.
But she was gone in seconds.
An amber alert was issued immediately. And 75 to 100 police officers from both Missouri and Illinois were quickly joined in the search by at least 50 volunteers and 30 FBI agents, Mergener says.