Julia Smith had already locked the doors to the Smoke Zone shop where she works in south Fort Worth.
About 10 minutes from closing time, a man she knew as a customer came to the door.
"[He was] banging on the door, banging on the door…did the ‘Please, please, please,' so I go and I open the door," said Smith.
Security camera video shows that the man was there to rob the store. He forced Smith into a back room and slugged her in the face.
"He hit me so hard I fell, and I caught myself," said Smith.
Smith says the robber hit her twice, though the video doesn't show the first blow. She says as he forced into the other room, he put a fist to the back of her head.
Smith still has headaches from the beating.
"My jaw, I can barely open it," said Smith. "It literally shook my brain inside of my head."
Smith says she was terrified of what could happen next.
"He kept screaming at me," she said. "He told me if I didn't shut the ‘F' up, I was going to die."
Smith says her job is helping pay her way through college. She wants to be a teacher.
She's speaking out because she doesn't want a similar incident to happen to someone else.
"If that little amount of money in ones and fives was worth beating up a 21-year-old college girl, I hope that money makes him happy," said Smith.
Smith says the suspect had been coming into the shop over the last couple of months. He was there earlier the same day he attacked her.
"You don't usually think about someone that smiles at you secretly being a shark," said Smith.
Police say the suspect is considered dangerous even though he didn't use any weapons.
He is described as a black man who is about 5-foot-10 to 6 feet tall. He is about 28-35 years old, weighs about 200 pounds and has distinctive tattoos on his arms.
He was seen driving a white Ford four-door vehicle, which could possibly be a Taurus.
Anyone with information on the suspect is asked to contact Fort Worth police at 817-392-4365.