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 accused killer to buy a gun.

The lawsuit comes a year after the mass shooting sent shock waves through the country. Dylann Roof, a white 21-year-old high school dropout, is charged with opening fire and killing nine people during a prayer meeting at the historic African American church. Prosecutors say the massacre was racially motivated.

In the days following the shooting, FBI Director James B. Comey said in a remarkable disclosure that Roof shouldn’t have been able to buy the gun. As The Washington Post story noted then:

Roof had been arrested for possession of narcotics in February, a charge that alone did not disqualify him from buying a gun. But Comey said Roof’s subsequent admission of the drug crime would have triggered an automatic rejection of his gun purchase if the information had been properly recorded in criminal-record and background-check databases.

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. And because of that delay during the background check, once the three-day mandatory waiting period for gun purchases expired, Roof was able to buy the .45-caliber Glock handgun.

“We are all sick this happened,” FBI director Comey said at the time. “We wish we could turn back time.”

In one of the multiple lawsuits filed Thursday, the victims’ families said, “If the gun sale was denied as required, it would have prevented the foreseeable harm to those people.”

Lawyer Andrew Savage said, “The victims and families hope that by bringing these actions, they can shine a very bright light on these shortcomings and prevent other individuals, families and communities from dealing with unfathomable and preventable loss and injury.”

Savage is representing three survivors of the attack as well as the relatives of five victims.

“It’s beyond a clerical error,” said S. Randolph Hood, an attorney for the wife of the Rev. Clementa Pinckney, who was killed in the shooting. If the federal government is going to be in control of who is allowed to buy guns, he said, “they need to do it right.”

Roof’s federal trial is scheduled to begin in November; his state trial is set for later this year, but is likely to be rescheduled. He faces the death penalty in both cases.

In the year since the church shooting, survivors and relatives of those killed have struggled to make meaning from the act of violence. Two weeks ago, marking the anniversary of the shooting, many of them at that same church to commemorate those killed and talk about the forgiveness, acts of grace and love they have witnessed in the months since.

“The incident has left many persons searching for a personal way to respond and counteract the hate and negativity that was the basis for the act,” said the church in a message for the event on its website, adding this quote from the Bible: “Let all that you do be done in love.”