HOUSTON -- A baby sitter was charged with endangering a child after police said she left a toddler alone in a car on Friday, KPRC Local 2 reported.

Officers were called to the St. Joseph's professional building shortly after 10 a.m. after a report of a girl locked inside a vehicle.

Investigators said the baby sitter, Juliet Castillo, left the 3-year-old strapped in her car seat so she could take her mother to an appointment.

Castillo told authorities that she thought it was only going to be for a few minutes, and she forgot about the child.

"I'm so very sorry. It was an accident," Castillo said.

"Did you just forget?" KPRC reporter Mary Benton asked.

"I just got too much in a hurry," Castillo said. "I don't know what happened."

The girl was left in the car for approximately 30 minutes. Temperatures reached nearly 100 degrees.

"She was sweaty from head to toe -- really red skin -- just normal signs of heat exhaustion," said Jason Beasley, a Houston Fire Department paramedic.

Several people pulling into the parking garage spotted the child. Someone picked up a rock and smashed the window to save the girl.

"I was completely shocked -- that somebody would be that crazy of doing something like that to a baby," witness Darnetta Beavers said.

"It's just too hot. That child wouldn't have made it. She wouldn't have made it," witness Barbara Beavers said. "She had a little hand reaching out toward me. And I said, 'Oh, Lord. I have to do something. What can I do?'"

The girl was taken to St. Joseph's Hospital and is expected to be OK.