The parents of Bo Rupp, the Centreville teen who was killed last fall after he sat down in the middle of a dark road and was hit by a sport-utility vehicle, sued the maker of the alcohol-infused drink Four Loko on Wednesday.

The parents said the 15-year-old drank two cans of Four Loko and didn’t know it would make him intoxicated and act irrationally.

Phusion Projects of Chicago, which makes Four Loko, issued a statement Thursday saying, “We are extremely saddened by this tragedy and our thoughts are with the Rupp family.”

The company noted that the drink was intended only for people 21 and older and that it has since reformulated the drink to remove caffeine and other controversial ingredients. Company officials said they would vigorously defend themselves in the litigation.

The lawsuit, filed in Chicago, says that one can of Four Loko had the alcohol equivalent of five to six cans of beer.

The suit alleges that Rupp and friends bought Four Loko at a gas station in Manassas, then went to a Sept. 25 concert at Jiffy Lube Live, where Rupp was ejected for being intoxicated. He allegedly drank two cans, but the caffeine initially masked the intoxication effects, the suit alleges.

On the way home from the concert, Rupp was paranoid and disoriented, then jumped out of the car in Centreville and fled from his mother, the suit states. Police said that Rupp was sitting on Pleasant Valley Road when he was struck by an SUV. He died a day later.