In an hourlong meeting at the Justice Department, the attorney general agreed with the participants’ request to present President Barack Obama with more than half a million signatures the survivors and family members helped gather.

The Tucson group supports legislation to expand background checks to include firearm sales by unlicensed dealers at gun shows and to list all purchasers with criminal records in the national instant criminal background check system. They want the two presidential candidates to say how they will deal with gun violence. Justice Department spokeswoman Tracy Schmaler called the meeting constructive and positive.