The little girl's mum, who was six and a half months pregnant, was attacked and robbed by two teenage boys in a supermarket car park. The brave five-year-old helped convict Nathaniel Moffett, 16, and Thaberi Francis, 18, by writing to Judge Darwall-Smith and telling him what happened.
The little girl wrote: "The boy punched my mum and hit the baby in her tummy. The other boy made sure nobody was looking. Now I don't like going shopping. I hope they don't hurt any more people."
Moffett and Francis carried out several knife attacks in Bristol during October and November, and all their victims were women, girls and boys.
The pregnant mum was attacked in the car park of Morrisons after she withdrew money from a cash point. They grabbed her arm, pushed her against her car and punched her stomach.
"I was so concerned about the baby being injured and my five-year-old daughter, who was very upset and crying. When I want to go out she asks me not to, because she does not want to go and is worried for me. Every two or three days she asks if the men have been caught or are still out there.
"I think if these two boys can do that to a pregnant woman with a small child, who else can they do it to?"
Both defendants pleaded guilty to robbery, attempted robbery and possession of bladed articles. They were jailed for 11 years in total.
Judge Darwall-Smith said: "These offences are the kind the public fear most - that is to see weapon robberies in public, at times when people are going about their normal business.
"In these exceptional circumstances the public has a right to know, and should know, what has been happening and what has transpired in respect of this 16-year-old and 18-year-old working together."