A woman fatally shot another woman in the head outside a gas station in Northeast D.C. on Monday, police say.

The shooting happened outside the Valero gas station at Minnesota Ave. and Ames Street NE shortly before 4 p.m., D.C. police said.

Medics rushed 21-year-old Tia Carey to a hospital, where she later died.

"She was only 21. So young. She didn't even get to see her baby grow up," Carey's mother, Demaris Carey, told News4 on Tuesday.

Carey was the mother of two girls, a 5-year-old and a 2-month-old. Demaris Carey is now taking care of her grandchildren.

"Senseless violence. I mean, you know, we encountered things every day? situations, but this was just an act of senseless violence," Demaris Carey said.

Witnesses and family told News4's Pat Collins that Carey had picked her daughter up from school and stopped at the gas station to get something to drink. They said she then got into an physical argument with the suspect, 21-year-old Tierra Posey.

The women were throwing punches at each other and then Posey allegedly took out a gun and fired two shots.

Witnesses said they had to physically sit on top of Posey to keep her from running from the scene.

D.C. police arrested Posey, of Southeast D.C., and charged her with second-degree murder while armed.