Attempts to build a memorial at the site of the shooting of former Rep. Gabrielle Giffords stalled because they became “politicized,” former Arizona Rep. Ron Barber said.

Survivors of the January 2011 shooting that killed six and severely injured Giffords and 12 others have raised more than $5 million to create a memorial in downtown Tucson.

But while the state House passed $2.5 million to help fund the project for the next five years, the Senate never took up the bill.

Crystal Kasnoff, executive director of the January 8th Memorial Foundation, told The Associated Press that she didn’t know why the bill didn’t get the same support it did in the House. But Barber, who was among those wounded in the shooting and later took over Giffords’ seat before losing his re-election bid, said he does.

“I’m really concerned that people who wanted to stop this memorial from being funded in the Senate decided to politicize it,” Barber told the AP. “And it’s not political, but that’s what they made it.”

Giffords, who stepped down from her seat in 2012, started a political action committee with her husband Mark Kelly to promote gun control.

Barber won Giffords’ seat in a special election in June 2012 and again in November of that year, but lost his re-election bid in 2014 to Republican Rep. Martha McSally.