Philadelphia ? A television group’s decision to air a documentary critical of Sen. John Kerry’s Vietnam antiwar activities has sparked a backlash from media watchdog groups and advertisers, and a lawsuit from a Vietnam veteran featured in the film.

Shares in Sinclair Broadcast Group, which intends to air the anti-Kerry film, “Stolen Honor: Wounds That Never Heal,” on all 62 of its stations across the country, traded at an all-time low Monday on Wall Street.

Monday, Kenneth J. Campbell, a University of Delaware professor who is one of the veterans depicted in the 41-minute film, sued the movie’s producer for libel, saying the film falsely portrayed him as a fraud and a liar.

In his suit, Campbell, said the film combined footage of his appearance at a 1971 war protest with a voice-over. The voice-over claims that many of the supposed veterans who took part in the event were later “discovered as frauds, who never set foot on the battlefield, or left the comfort of the States, or even served in uniform.”

“They put me in it as almost a centerpiece example of a fraudulent, lying pseudo-veteran,” said Campbell. “I thought about it, and could not let it pass. I nearly lost my life in Vietnam multiple times and to have someone say I am a fake and a fraud and didn’t even serve in Vietnam is utterly despicable.”

Also Monday, the Washington bureau chief for Sinclair Broadcast Group was fired after he criticized the company’s plans to produce a news program based on the documentary. Jon Leiberman, 29, had criticized his employer in an interview with The Baltimore Sun published Monday.