Transcript for NASCAR's Tony Stewart Takes on a Fan
the missing. And some unsportsmanlike behavior from a NASCAR superstar tonight. Tony Stewart caught on camera, barrelling into the stands, taking on a fan who's heckling him. Stewart has been fined for acting before. He's also facing a wrongful death suit. Tonight, a new investigation. He here's ABC's Mary Bruce. Reporter: It's the kind of drama racing fans expect to see on the track. NASCAR superstar Tony Stewart storming into the stands. I don't like you and I never have. Reporter: Caught on tape in a heated clash with a heckler. You're a , aren't you? No, I'm not. Reporter: The three-time sprint cup champion is notoriously hot-headed. He was placed on probation for slamming into a competitor in this post-race skirmish in 2014. One of the requisite skills to be a public figure is to have thick skin. And ignore this kind of criticism. Reporter: This latest outburst comes as Tony Stewart faces a wrongful death lawsuit. He's accused of losing his temper and driving recklessly before striking and killing fellow driver, 20-year-old Kevin ward Jr. I know in my heart that it was a 100% an accident. Reporter: Stewart has yet to comment on this new incident. But the fan involved, an off-duty law enforcement official, is being investigated by his department to see if he acted improperly. Mary Bruce, ABC news, Washington.
This transcript has been automatically generated and may not be 100% accurate.