India, Oct. 26 -- The Dallas Police Department has issued a critical update amid a search for a missing 13-year-old girl. Natalie Armstrong has been designated as an endangered missing person who "may be in need of assistance," per ABC.

Natalie was last seen on foot at 10:08 p.m. Wednesday, October 21 in the 9300 block of Whistle Stop Place in the Lake Highlands area of Dallas. She has been described as 5 feet 3 inches tall, weighing approximately 135 pounds. She has brown hair and hazel eyes.

Natalie was last seen wearing a gray hoodie, blue jeans, and white shoes.

Natalie's mother, Megan Bernhardt, said that her daughter has autism, and is concerned that she could put herself in danger without realizing it.

"She's on the spectrum, b...