TULSA, Oklahoma - A Tulsa mother said what started as a fight between two 13-year-old boys escalated into full-out assault by an adult.

She said, in retribution for the fight, her son was later beaten by a man in a mask with a gun, and now has a concussion and swelling of the brain.

Carletta said the sight of her 13-year-old's blood on the ground and wall where he was beaten breaks her heart and makes her angry.

She said he and another 13-year-old boy got into a fight last Thursday at the bus stop after school.

Carletta said both boys were told they would be suspended, so she thought it was over, until her son was at the same bus stop Tuesday morning and a grown man showed up, looking for her son.

"The masked man with a gun on a bicycle called my son out, said, ‘Hey you, come here.' He started running and the man caught him and he beat him bad, real bad," Carletta said.

She said her son was beaten unconscious and brought home by a Good Samaritan.

Carletta said he has a concussion, swelling in the brain, staples in the back of his head and marks on his face, elbows and knees.

"Two 13-year-old boys, you fight all the time, you win some, you lose some, but to carry it on to an adult level—now you're asking for more trouble. [It] should never have gone there," Carletta said.

She filed a police report and talked to the school and said the school has someone monitoring that bus route to make sure there is no more trouble.

Carletta said she wants the man caught, even though she knows it'll be tough, since his face was covered.

She said she believes he is related to the other boy.

"Whoever you are, if you've got a conscience, if you've got a child, give yourself up, because sooner or later you will be caught. Because I'm not letting this go until justice is done," Carletta said.

Students at the bus stop told News On 6 that the other boy's uncle came there on Friday and was asking about the fight the night before, demanding to know who was involved.

They said they believe he's the same man who came back Tuesday with a mask and did the beating.