A man charged with stabbing a Metrobus driver on Wednesday had struck the driver with a cart and refused to apologize, sparking an argument that led to the attack, according to an arrest affidavit filed in court.

The suspect, Robert Vossburg, 21, who has no fixed address, was charged with assault with a dangerous weapon and ordered detained until his next hearing in D.C. Superior Court. Authorities had previously said Vossburg was 19 years old.

Police said the stabbing occurred about 10 p.m. on the A8 route near Martin Luther King Jr. Avenue and First Street in Southeast. The driver was treated at a hospital for a severe cut to his arm.

The affidavit says that Vossburg boarded the bus on Martin Luther King Jr. Avenue and struck the driver with the cart. The suspect, police said, “failed to apologize or excuse himself.” The driver, police said in the court document, “expressed his displeasure” and the two began to argue.

Police said the suspect sat down but then got up at the next stop and the argument resumed. The affidavit quotes Vossburg saying, “I just got out of jail. I don’t care about going back and I don’t care about your life.” Police said Vossburg spit on the driver, then cut him with a tile cutter as the two struggled.

Vossburg ran off the bus, according to the affidavit, and was arrested by police in nearby woods.

Earlier this week, a passenger told The Post that the argument occurred when the bus driver accidentally elbowed Vossburg while asking him to pay the bus fare.