The imagery is iconic: A Texas state trooper approaches a stopped car, driven by Sandra Bland, a 28-year-old woman who would be found dead in a jail cell three days later.

That 2015 dash-cam video is now the opening of a campaign commercial in the race for Pennsylvania attorney general - and Bland's mother wants it pulled off the air.

That has sparked a new clash between two of the Democrats in the race, Allegheny County District Attorney Stephen Zappala, who used the video in his first ad last week, and Montgomery County Commission Chairman Josh Shapiro, who alerted Bland's family.

It is also part of a larger statewide struggle between Zappala and Shapiro, both white, to showcase support from African American leaders in the run-up to the April 26 primary.

Zappala's campaign on Tuesday said the ad would stay on the air, and blamed Shapiro for "orchestrating a controversy where one does not exist."

On Tuesday, Zappala sounded disconnected from the controversy when asked about it during a campaign stop in Philadelphia to tout support from African American and Latino leaders.

"I didn't know there was criticism," Zappala replied when asked about a news conference Shapiro held last Thursday, along with some of his black supporters, to condemn the ad.

Zappala said twice that he did not know of anyone having contacted his campaign to ask that the video be taken out of the ad.

"Decisions on these campaigns at this level are made by the media people, ultimately what they want to run and don't want to run," he said.

Cannon Lambert, a lawyer in Chicago who represents Geneva Reed-Veal, Bland's mother, said a letter he sent to Zappala's campaign on Friday "was really clear and enunciated" a request to stop using any imagery associated with Bland's traffic stop.

"She's uncomfortable with that and has let them know that," Lambert said. "She would be disappointed if they forgo that request."

Ken Snyder, the consultant who created the ad for Zappala, said Lambert's letter asked the campaign to stop using Bland's image or implying that her family endorses Zappala.

Bland's face is not visible in the ad, and her name is not mentioned. Snyder said the ad does not imply an endorsement from Bland's family.

"Josh Shapiro has clearly orchestrated a controversy where one does not exist because he is afraid to discuss the important issues depicted in Steve Zappala's opening ad," Snyder said Tuesday.

The ad uses the video to help tout what Zappala says is his record as a prosecutor of fighting racial profiling and domestic violence, and of applying tough scrutiny to use of force by police officers.

The ad includes another 2015 video that has become part of the Black Lives Matter movement: a policeman shooting Walter Scott as he ran from an encounter in North Charleston, S.C. It also includes the 2014 surveillance video of then-NFL running back Ray Rice in an Atlantic City casino after he punched his fiancee.

Shapiro's campaign said it alerted families connected with the three videos "that images of their tragedies" were in the ad.

His campaign said in a statement, "It's unfortunate that Zappala has decided to continue running the ad and ignore the request of Sandra Bland's family."

215-854-5973 @ByChrisBrennan