Here is the latest on an unimaginable crime, a mass shooting June 17 inside an historic church:

What happened: Police believe Dylann Storm Roof, 21, opened fire during a prayer meeting Wednesday night inside Emanuel AME Church, a historic black church in Charleston, S.C. Nine people were killed, including three men and six women. Among those killed was the church pastor, the Rev. Clementa Carlos Pinckney.

The suspect: Roof, of Lexington, S.C., came into the church during a bible study, sat next to the Rev. Pinckney, according to some media reports, and was inside for an hour before the 9 p.m. shootings, according to police. He was seen leaving the church in a black, four-door sedan. Just before 11 a.m. Thursday, Roof was arrested during a traffic stop in Shelby, N.C., about 250 miles away, according to Charleston police.

The pastor: Pinckney 41, was a married father of two. He was first elected to the South Carolina House at age 23 in in 1996. He was elected to the state Senate at age 27. He was a graduate of Allen University in Columbia. He earned a master's degree in public administration from the University of South Carolina in 1999 and studied at the Lutheran Theological Southern Seminary. A native of Beaufort, Pinckney began preaching at age 13 and was first appointed pastor at 18. He was named pastor of Emanuel AME Church in 2010.

Other victims: Cynthia Hurd, 54; Tywanza Sanders, 26; Sharonda Singleton, 45; Myra Thompson, 59; Ethel Lance, 70; Susie Jackson, 87; the Rev. Daniel Simmons Sr., 74; and DePayne Doctor, 49. The president of Allen University in Columbia confirmed that Saunders, like Pinckney, was an alumni. President Lady June Cole said he was a 2014 Allen graduate in business administration.

The investigation: The Justice Department's Civil Rights Division, the FBI and the U.S. Attorney's Office for South Carolina have opened hate crime investigations.

The church: According to The Post and Courier in Charleston, the historic Charleston congregation was formed in 1816, the first African Methodist Episcopal church in the South, and it remains oldest south of the Mason-Dixon Line. Among its founding members was Denmark Vesey, who plotted a slave rebellion from the same location about 193 years earlier. The church was burned down after the revolt failed and Vesey and 34 others were hanged. The church was eventually rebuilt on the same location.Pinckney was named pastor in 2010. Several historic figures have spoken at the church, including Booker T. Washington in 1909 and the Rev. Martin Luther King Jr. in 1962. Coretta Scott King led a march there in 1969, according to reports.

What they're saying: "This type of mass violence doesn't happen in other advanced countries," said President Barack Obama in a Thursday afternoon press conference.

“The only reason someone would walk into a church and shoot people that were praying is hate,” said Mayor Joe Riley.

“There is no greater coward than a criminal who enters a house of God and slaughters innocent people engaged in the study of scripture,” said NAACP President and CEO Cornell William Brooks.

— The Associated Press and various media sources contributed to this report.