Police said Stacie McCullough walked up to the 68-year-old victim and asked for directions.

When the woman said she didn’t know, McCullough tossed a cup of yellow liquid in her face and snatched her purse, according to police.

McCullough was also armed with a knife, police said.

“It surprised me someone would do that anywhere, so that person is not in their right mental state to do that to another human being,” said a Publix customer, who did not want to be identified.

A good Samaritan confronted McCullough and got the victim’s purse back.

Witnesses followed McCullough, and police arrested her a short time later.

McCullough claimed that the victim attacked her and told police that she suffers from bipolar disorder.