A South Carolina man, accused of planning an attack "in the spirit of Dylann Roof," was arrested by FBI after he bought a gun in the Myrtle Beach area. Benjamin Thomas Samuel McDowell, 29, is a convicted felon.

McDowell bought a .40-caliber Glock, FBI agent Grant Lowe wrote in an affidavit, reports USA Today. The arrest came after several weeks of tracking and interacting with McDowell, the FBI said in a NBC News report.

After a December Facebook post by McDowell about a synagogue in Myrtle Beach, authorities began to monitor him. His expletive-filled posts on Facebook complained about Jewish people destroying "the white man," and about people being willing to have the heart to do what Roof did.

McDowell also appeared to reference an early January video that showed four young black people beating a disabled white teen that was streamed on Facebook Live.

Horry County Police kept track of McDowell since his release from prison on felony burglary charges a few years ago because he made connections with white supremacists while behind bars, according to the affidavit.

According to a criminal complaint filed in federal court, McDowell, of Conway, S.C., referenced Dylann Roof, the man convicted of the racially motivated killing of nine African Americans at Emanuel African Methodist Episcopal Church in Charleston, S.C., in 2015. Roof was sentenced to 18 death sentences and 15 life sentences, the statutory maximum for each of the 33 federal counts lodged against him in January.

After putting a message on Facebook that he wanted "iron," or a gun, McDowell agreed to meet with an undercover FBI agent to make the purchase. McDowell believed the person handled problems for the Aryan Nations. The agent said McDowell voiced frustration over other white supremacists, saying that screaming "white power" wasn't getting the job done.

He told the agent, according to the complaint, that he was looking for a way to conduct an attack on non-whites without getting caught.

"I seen what Dylann Roof did and in my heart I reckon I got a little bit of hatred," McDowell reportedly said. According to the complaint, he added, he wanted to do something on a big scale and write "In the spirit of Dylann Roof."

During ongoing communication with the undercover agent, the testimony said, it was revealed that McDowell was talking on his mother's landline and cellphone. The agent also allegedly agreed to pick McDowell up at his mother's house, then drive to his grandfather's home where he planned to borrow money to buy the gun.

In one phone call, the undercover agent said McDowell wanted him to get the gun because he intended to conduct the attack outside Horry County, where he lived.

As a convicted felon, McDowell was prohibited from having a gun.

McDowell again asked the undercover agent for a gun and asked for hollow-point ammunition.

The two agreed to meet Wednesday at a motel in Myrtle Beach. After paying $109 for the gun, the FBI arrested McDowell. He is charged with being a felon in possession of a firearm. The firing pin was filed down on the gun McDowell was sold, Lowe wrote.

Court records show that since 2008, McDowell has several convictions for burglary and a conviction for assault, reports USA Today.