President Obama spoke about the Charleston, South Carolina, church shooting in the White House Thursday. He expressed “deep sorrow over the senseless murders” in South Carolina.

Obama said that he and his wife, Michelle, knew several members of Emanuel AME Church. He said that he also knew Reverend Clementa Pinckney, the pastor who was among the nine people killed Wednesday night.

While the U.S. president acknowledged that any such death was a tragedy, this massacre was “particularly heartbreaking” since it happened in a place of worship. He added that people sought peace and solace in such a place.

Obama spoke highly of the church, which had been founded by Afro-Americans seeking liberty. “When there was a nonviolent movement to bring our country closer in line with our highest ideals, some of our brightest leaders spoke and led marches from this church’s steps,” TIME quoted the president, “This is a sacred place in the history of Charleston and in the history of America.”

The U.S. president said that he would not be able to talk about the details of the case since the investigation was still going on. Obama said that innocent people had been killed once again because someone with an intention to harm “had no trouble getting their hands on a gun.”    

Charleston police named Dylann Roof, 21, as the lead suspect in the church shooting. CNN quoted Sylvia Johnson, the cousin of the pastor killed in the shooting, who said that the suspect had blamed the church crowd for “raping American women and taking over the country” before opening fire.

Roof was arrested and taken into custody in Shelby, North Carolina. The suspect had a gun when he was arrested at around 11:15 a.m. Thursday during a traffic stop. However, it was not clear if this was the same gun used during the shooting.

Obama said that the FBI was working with local police on the case. He said he was aware that the suspect had been arrested. Obama added that he would make sure justice was served.