Former Arizona Rep. Gabrielle Giffords’ anti-gun PAC is changing an advertisement it is running against Colorado GOP Rep. Mike Coffman after the father of a girl who was killed in a school shooting in the state 12 years ago criticized it for appearing to use his daughter’s death to score political points.

The Denver Post first reported this story.

John-Michael Keyes’ daughter Emily was killed by a gunman who took her and other students hostage at Platte Canyon High School in September 2006.

Today is the 12th anniversary of Emily Keyes’ death. She had been texting her twin brother and parents throughout the ordeal. Her last message: “I love U guys.”

“Tomorrow is the 12th anniversary of losing Emily, and to see that story politicized is disappointing,” John-Michael Keyes told 9NEWS in Colorado on Tuesday.

In Giffords PAC’s 30-second ad, a text exchange between a girl named Emily and her mother unfurls on screen. The Emily from the ad tells her mother she is in social studies and that the school is on lockdown because someone has a gun.

When Emily’s mother asks if she’s OK, she responds, “Yeah but I’m so scared. I love u. Tell Dad I love him.”

The fictitious Emily does not respond to her mother’s subsequent texts.

The ad then cuts to a narrator who points who points out that the National Rifle Association has given more money to Coffman than any other Colorado member of Congress.

Coffman, who is ninth on Roll Call’s list of the 10 Most Vulnerable House Members, said in a statement that he respects Giffords, who was shot and nearly killed in a 2011 constituent event in Tucson, Arizona, “but exploiting the name and horrible death of one of our own to try to win an election is beneath basic human dignity.”

“I can take criticism, but this is reprehensible,” Coffman said. “This ad should be pulled and someone should be fired.”

Giffords PAC will not take the ad off the air for now, a spokesman told the Post. But it will modify it out of respect for Emily Keyes.

“This ad was not modeled after any one individual tragedy. We are amending the ad, removing a name all together and making clear that it is not connected to any one incident,” Giffords Executive Director Peter Ambler told the Post in a statement. “Given how many families have experienced gun violence tragedies, there isn’t any name we could have used that wouldn’t be connected to a victim somewhere.”

Giffords PAC is sinking $1.5 million into the effort to unseat Coffman — more than the group has put into any other race so far this cycle, The Colorado Sun reported.

Coffman, who has an A rating with the NRA, is defending his seat against Democrat Jason Crow in Colorado’s 6th District, where Hillary Clinton beat President Donald Trump by 9 points in 2016.

Inside Elections with Nathan L. Gonzales rates the race Tossup.

Watch: We Reviewed Andy Barr, Amy McGrath and Beto O’Rourke’s New Campaign Ads