(Photo by Bill Morrow - CC BY 2.0)

Former Congresswoman Gabrielle Giffords.

It’s been nearly six years since a mass shooting in Tucson claimed the lives of six people and injured 13 — including former Congresswoman Gabby Giffords. Now the effort to build a memorial for the victims and survivors needs more money.

Crystal Kasnoff, the executive director of the January 8th Memorial Foundation, said the tribute in downtown Tucson will cost an estimated $4.5 million, and construction could begin in July. Kasnoff said her group is trying to fundraise by airing public service announcements.

One of the PSAs features the father of Gabby Giffords’ aide Gabe Zimmerman, who died in the gunfire. Another spot has Giffords’ husband, Mark Kelly.

On Jan. 8, 2011, Jared Loughner opened fire outside a Tucson supermarket. The dead ranged in age from 9 to 79. Giffords, then a US representative, was shot in the head but survived. Loughlin is serving a life sentence.

The Associated Press contributed to this report.