Charleston race killer Dylann Roof originally planned to shoot up a college before changing his mind and massacring worshipers in church, according to a shocked black drinking buddy who counted Roof as a 'homeboy'.

Christon Scriven, 22, said that Roof drunkenly described a scheme to massacre students on the College of Charleston campus just a week ago.

But Roof seemingly modified his plan when he sat in on a Bible study class at the city's AME Emanuel Church for almost an hour, then opened fire on his nine victims.

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'Homeboys': Christon Scriven, right, said that killer Dylann Roof, left, was planning to attacked the College of Charleston, but instead targeted his racist massacre at the AME Emanuel Church in the South Carolina city

Scriven said he didn't believe Roof would actually carry out his plans for a mass shooting - but was still scared he could turn violent, so hid his gun when he wasn't looking.

He and another friend - Roof's high school pal Joey Meek - stashed his .45-caliber handgun, a birthday present, in an air condition vent, but gave it back once they had all sobered up.

Roof would go on to use the weapon in the church massacre just days later. Scriven has said he and other friends are now racked with guilt at the thought they could have done something to prevent the shootings.

He opened up about his friendship with Roof on Friday, the same day the killer made his first court appearance, and was formally charged with the nine murders, for which he could face the death penalty.

Scriven said the young men would often drink in the Lexington, South Carolina, trailer park along where he lives next door to Meek, who originally introduced the two.

Drinking buddies: Joey Meek, left, was a mutual friend who introduced Roof and Scriven (right). The three would often drink together at a trailer park in Lexington, South Carolina

Charges: Roof, pictured under armed guard appearing via court video link, has been charged with murdering nine people on Wednesday night

'One night we all got drunk together and since then, me and Dylann were just homeboys,' Scriven said. 'We would just chill every day.'

Describing Roof's plan for a college shooting, he said: 'He just said he was going to hurt a bunch of people.'

'I said: "What did you say? Why do you want to hurt those people in Charleston?"'

'He just said: "In seven days. ... I have seven days."'

Scriven speculated that Roof could have backed down from attacking the College of Charleston once he realized it has security.

He said: 'I don't think the church was his primary target because he told us he was going for the school. But I think he couldn't get into the school because of the security... so I think he just settled for the church.'

Roof has reportedly confessed to the killings while talking to investigators, and said that he hoped his actions would spark a race war.

Target: Scriven said that Roof had spoken of the College of Charleston, pictured, as the place he wanted to attack. He speculated he may have chosen a church instead because of college security

Smirk: Roof seemed bemused as he was taken from a jail in North Carolina, where he was caught, back to his home state to face murder charges - for which he could ultimately be executed

Survivors of the attack said they heard tell his victims he was killing them because black people 'rape our women' and are 'taking over our country - and you have to go'.

On his Facebook profile, Roof posted a photo of himself wearing a jacket adorned with the flags of the now defunct white-supremacist regimes in South Africa and Rhodesia.

But Scriven said that he never spoke with Roof about race, instead chatting about fishing, NASCAR and guns. Roof's now-deleted social media accounts also listed several black people as friends.

Victims: Nine people died in the shooting. They are (top row, left to right) DePayne Middleton-Doctor, Tywanza Sanders, Myrah Thompson, (center row) Ethel Lance, Susie Jackson, Sharonda Coleman-Singleton, (bottom row) Daniel Simmons, Clementa Pinckney and Cynthia Hurd

One of them, Caleb Brown, knew Roof in grade school and high school. He said: 'He never once said anything to me derogatory, racist, anything like that. Otherwise we would have not been friends.'

Speaking to CBS News, he said neither Roof nor his family seemed to be hateful people.

He said: 'If something in him turned, then it was recent. It wasn't his whole life; he wasn't sitting, bubbling with hatred towards black people - no, that just happened and I don't know why.'

But Roof's other drinking buddy, Meek, who is white, said Thursday that he had heard Roof drunkenly make racist rants in the past.

Childhood friend: Caleb Brown, who went to grade school and high school with Roof, said that he had never heard anything racist from him when they were younger

He said that between sips of vodka, Roof would say that ''blacks were taking over the world' and that 'someone needed to do something about it for the white race.'

Scriven said that in the course of their friendship, Roof confessed that he was unhappy, bouncing between the homes of his divorced parents.

He would stay for days at the mobile home park, smoking American Spirit cigarettes and drinking hard, before going home for a few days to get clothes and money.

Scriven said he could tell Roof was depressed, and that he complained that he wasn't getting the love and emotional support he needed from his parents. When he got upset, Roof would retreat to his car, blasting a cassette tape of opera.

He said: 'I don't think his parents liked his decisions, the choices that he made to have black friends,' Scriven recounted.

'His mom had taken the gun from him and somehow he went back and took it from her. ... That's when we saw the gun for the first time: .45 with a high-point laser beam.'

Target: Pictured is the AME Emanuel Church in Charleston, shown Friday, two days after the shooting

While they were drinking, Scriven and Meek decided to hide the gun in case Roof did anything violent. They stashed it in an air conditioning vent, but later handed it back.

When Scriven saw this week that Roof was arrested, he said it hit him 'that he actually did all the stuff he said he was going to do, like he actually killed these people.'

Though none of them took the statements seriously, Scriven said he and Roof's other friends are now struggling with the knowledge that they might have been able to prevent the killings.