The families of victims killed in last year’s shooting at the Emanuel AME Church in Charleston, S.C., are suing the FBI over an error during a background check that allowed the alleged shooter to buy his gun. The lawsuit comes a year after the mass shooting that sent shock waves through the country. Dylann Roof is charged with opening fire and killing nine black parishioners during a prayer meeting at the historic African American church. In the days after the shooting, FBI Director James B. Comey said in a remarkable disclosure that Roof shouldn’t have been able to buy the gun he allegedly used. Authorities have said that a clerk’s mistake in how Roof’s arrest was listed prevented the FBI examiner for his background check from seeing it. Roof’s federal trial is scheduled to begin in November; his state trial is also set for later this year but is likely to be rescheduled. He faces the death penalty in both cases.