CONWAY, S.C. (AP) — The mother of a man who authorities say wanted to kill Jewish or black people in an attack inspired by Dylann Roof said her son thought it was time for white people to stand up for their rights.

Joanne Strickland said she saw her son leave their house with a Bible on Wednesday, then several hours later, federal agents were knocking on her door with a search warrant, saying they had arrested the 29-year-old felon who sought out a gun for what he said would be an attack in the "spirit of Dylann Roof."

"I raised him better than that. Me and my ex-husband had him in church every Sunday," Strickland told WBTW-TV (http://bit.ly/2l1uNOQ ).

The FBI said it began investigating Benjamin McDowell after he threatened a Myrtle Beach synagogue on Facebook in December. Local officials were already monitoring him because he had made friends in prison with white supremacists, the FBI said in court papers.

McDowell said he wanted to buy a gun for an attack similar to Roof's massacre of nine black church worshippers in Charleston in June 2015, according to an undercover FBI agent who sold him a weapon for $109 on Wednesday.

McDowell was arrested a few hours later and charged with being a felon in possession of a weapon. The FBI said McDowell didn't share a specific target for an attack, but said he did not like black or Jewish people.

Roof was sentenced to death in January, and during his trial Strickland said her son called him brave for standing up for white people even if Roof shouldn't have killed people at a church.

"He said the way the Black Lives and all that is doing what they're doing — they're out there getting by with that," Strickland said. "And if any of us, you know, was to stand up for that for us, it would be awful. He said that's not right they can stand up and we can't."

McDowell's neighbors said Strickland asked them to keep an eye on her because she had a difficult relationship with her son. Strickland said he started getting in trouble as a teen, and McDowell has several burglary convictions.

Both Strickland and a neighbor said McDowell had talked about going to Alabama to start his life over. Sammi Charbonne, who lived down the street from the family, said McDowell told him he was worried two days before he was arrested.

"Maybe that was him being scared to do what he had planned?" Charbonne told The Sun News of Myrtle Beach (http://bit.ly/2m9dusI).