The profile picture on Dylann Storm Roof's Facebook page shows a young man staring with dead eyes into the camera while wearing a black jacket with flag patches of white-ruled Rhodesia and apartheid-era South Africa.

What was behind the eyes was apparently an introvert with few friends, who reportedly used drugs and had prior run-ins with the law.

Roof, 21, gunned down nine people inside historic Emanuel African Methodist Episcopal Church in Charleston, South Carolina Wednesday night, authorities said. He was arrested without incident Thursday morning about 240 miles away in Shelby, North Carolina.

"He was like a pill popper, from what I understand. Like Xanax, and stuff like that"

- John Mullins, who attended high school with suspect

Details about what unfolded inside the church are unclear, but a woman who spoke to a witness told NBC that the gunman, who attended the meeting for an hour, asked to sit next to the pastor and said, "I have to do it. You rape our women and you’re taking over our country. And you have to go."

At least two people survived the attack. One was reportedly a five-year-old girl who obeyed her grandmother's instructions to play dead and the other was a woman whom the gunman freed to "tell the world" what happened, according to reports.

The Department of Justice announced it will investigate the shooting as a hate crime.

In addition to the Facebook picture, Roof was known to drive around with a Confederate flag on his license plate, which is not unusual in the South. A friend reportedly posted a picture on Facebook of Roof sitting on the hood of a black car with the plate that read, "Confederate States of America."

The New York Times reported that Roof's current address is listed as Eastover, a small town southeast of Columbia with a large African-American population.

The Southern Poverty Law Center, a civil rights group that tracks hate organizations and extremists, said it was not aware of Roof before the rampage. And some friends say they did not know him to be racist. One friend from White Knoll High School said Roof had black friends. The Daily Beast reported that many of his friends on Facebook are also black.

"I never heard him say anything, but just he had that kind of Southern pride, I guess some would say. Strong conservative beliefs," John Mullins, who went to school with Roof, told The Daily Beast. "He made a lot of racist jokes, but you don't really take them seriously like that. You don't really think of it like that."

Mullins, however, told the news site that Roof used drugs.

"He was like a pill popper, from what I understand. Like Xanax, and stuff like that," he said.

Roof attended ninth grade at White Knoll High during the 2008-09 school year and went there for the first half of the following academic year, district spokeswoman Mary Beth Hill said. The school system gave no reason for Roof's departure and said it had no record of him attending any other schools in the district.

Roof also had a few recent run-ins with the law. The Post and Courier reported that he was arrested twice in South Carolina and was jailed in March in Lexington County on a drug charge.

The Times, citing a police report, said that Roof was arrested in February at a shopping center after asking employees unusual questions, such as what time they'd be off work. A police officer reportedly found the prescription drug Suboxone on him and he was arrested. The case is pending, the report said.

It was one of Roof's childhood friends, Joey Meek, who alerted the FBI Thursday after recognizing him in a surveillance camera image that was widely circulated, according to Meek's mother, Kimberly Konzny. Roof had worn the same sweatshirt while playing Xbox videogames in their home recently.

"I don't know what was going through his head," Konzny said. "He was a really sweet kid. He was quiet. He only had a few friends."

Carson Cowles, Roof's uncle, told Reuters that several years ago he became concerned about his nephew who "stayed in his room a lot of the time."

He said Roof did not have a driver's license or job at the time. He said he tried to mentor his nephew, but the two ended up drifting apart.

He recalled earlier this year when his nephew received a .45-caliber pistol from his father-- who runs a construction business-- for his 21st birthday.

"I actually talked to him on the phone briefly for just a few moments and he was saying, 'well I'm outside target practicing with my new gun,'" Cowles told Reuters.

"Nobody in my family had seen anything like this coming," Cowles said.

The Associated Press contributed to this report

Follow Edmund DeMarche on Twitter @edemarche

Edmund DeMarche is a news editor for FoxNews.com. Follow him on Twitter @EDeMarche.