Attorneys for a man charged with killing nine people at a South Carolina church are continuing their push to persuade a judge to dismiss charges in the case.

Dylann Roof's attorneys say in court filings Monday that prosecutors must prove the shooting affected interstate commerce to charge him under federal hate crimes laws. And they say any connection between the June 2015 shooting in Charleston and interstate commerce is vague.

Prosecutors contend the 22-year-old Roof used the internet to scope out Emanuel AME Church, drove on interstate highways to and from Charleston, and used a gun made outside South Carolina.

The defense wants the charges dismissed and says other courts have struggled with how a crime substantially affects interstate commerce.

Roof faces 33 federal counts in a November death penalty trial.