Like Emanuel, the Branch church was holding its weekly Bible study that night.
The Bible study at Branch AME had been canceled that night, the church's Rev. Rufus Berry told the Post and Courier newspaper. His GPS device deactivated for approximately two to three minutes, which is consistent with stopping the vehicle, according to prosecutors. Even if the gathering hadn't been canceled, it would've been over by the time Roof arrived, he said.
Roof's legal team sought to keep the Branch AME information out of his trial, noting in documents of their own that the church - one of more than 500 AME congregations in SC - was merely near his route from Charleston to North Carolina and that the government had no evidence Roof had planned an attack there. He is now being held at the Charleston County jail while he awaits a state trial on murder charges stemming from the attack. But Berry told the Charleston newspaper that he was unsettled by the news.
Global Positioning System data revealed Roof's itinerary to investigators, court records not presented in the trial showed, according to ABC News.
British parliament debates Trump visit
The government insists the US President's trip will go ahead - despite nearly two million people signing a petition against it. All petitions with more than 100,000 signatures are eligible for debate in parliament - but not a binding vote.
In the motion, Roof's attorneys argued his case happened entirely in SC and involved only "incidental and everyday use" of areas affected by the commerce clause, like the internet or purchases from another state.
Prosecutors argue that this shows Roof was contemplating another attack, but defense attorneys have said there is no evidence of this.
The GPS data was not presented during his trial.
In December, a jury convicted Roof of 33 federal charges for killing nine Bible study goers in cold blood as they prayed. He is the first person to get the death penalty for a federal hate crime.