Police say 22-year-old Los Angeles resident Fu Sheng Situ trailed the girl around an Alhambra Kohl's Wednesday night before following her into the woman's dressing room. Situ then slipped his smart phone under the dressing room door in what police said was an attempt to record the child undressing.
"A male subject entered the women's changing room at Kohl's department store this afternoon and tried to use his cell phone to take pictures of a 10-year-old girl trying on clothes," local police statement confirmed in a statement.
But the girl noticed the device and, apparently familiar with how camera phones work, notified her mother who immediately hailed store security.
"This kid was really sharp," Alhambra Detective Sgt. Jim Hammond told NBC Los Angeles.
"The mother didn't even catch this."
Situ surrendered peacefully to authorities on suspicion of child annoyance, but was released without further charges until a warrant is issued to search his cellphone.
"Obviously, the phone is going to tell us truly what he's involved in."