A 14-year-old Detroit boy is in critical condition after he was stabbed Wednesday while riding a city bus near Dexter Avenue and Lawrence Street.

DeJon McGhee was on a Detroit Department of Transportation bus with other teens when two men -- one white and the other black -- started having an argument.

Police say the argument was racial. They were talking about Martin Luther King Jr. and the black man apparently claimed to have killed MLK.

The group of students, who all happen to attend Detroit's Martin Luther High School, told the black man he was wrong, telling them that's not what happened. They told him he was talking nonsense.

"He called him names, he called him a (expletive). Then he told him that he killed MLK, something like that," said Precious Jones, one of the students who was on the bus. "Everybody kind of got upset on the bus."

Precious said her classmate DeJon started arguing with the man. The black man got into DeJon's face and kept asking the teen if he wanted to fight, police say. They all exited the bus at that point and the man picked a fight with the teen.

"The man got off the bus and he told him, 'If you want to fight, come on,'" she said.

Witness Zubari Robinson said something seemed wrong with the man.

"Something was probably mentally wrong with him or he was under the influence of something," he said.

Police say DeJon was defending himself when he punched the man in the nose. The man then took out a knife. The teen ran back onto the bus saying the man had a knife.

"Once (DeJon) saw the knife he ran back on the bus," said Precious.

The man followed him onto the bus and stabbed him in the chest.

"He was holding his chest and I didn't know what happened but then once he let it go we saw a lot of blood just fall," she said.

The teen is in critical condition at Henry Ford Hospital. His classmates are praying for him.

"I just hope he's OK," said Precious.

Detroit police have not announced any arrests.

The suspect is described as an adult black man in his 40s or 50s. He was wearing an orange sweater, a green winter coat and red hat with a "D" on the front. 

Stay with for more information as it becomes available.