The suspects were visiting the funfair together with two other people on Saturday night. The four were seen fleeing the scene of the crime, the Rhineland-Palatinate state police said.
"The suspicion against two men in this group, aged 25 and 26, was later confirmed. They are US military servicemen… The state prosecutor’s office in Trier handed over the case to American prosecutors in accordance with NATO statute," police said.
The two suspects were likewise handed over to the Office of Special Investigations at US Airbase Spangdahlem, which took charge of the murder probe. The base is located not far from Wittlich.
Regional broadcaster SWR reported that the 28-year-old victim was stabbed near his Wittlich home. He was identified as a manager of a security firm who was on his way home when the quarrel broke out.
Wittlich Mayor Joachim Rodenkirch said in a short speech at the market square that he was "horrified and terribly saddened by the brutal death of a young man" and offered his condolences to the bereaved family.