Her father says Krystle Campbell, of Medford, Mass., had gone with her best friend to take a picture of the friend's boyfriend crossing the finish line on Monday afternoon.
William Campbell says his daughter, who worked at a restaurant in nearby Arlington, was "very caring, very loving person, and was daddy's little girl." He says the loss has devastated the family.
He says the friend was seriously injured in the explosion.
An 8-year-old, Martin Richard of Boston, also died. He was at the finish line watching the race with his family.