JACKSON (AP) — Charles Marcus Edwards testified Tuesday that he and fellow Klansman James Ford Seale abducted and attacked two black teenagers in southwest Mississippi in 1964.

Edwards has been granted immunity to testify in the federal kidnapping and conspiracy trial of Seale, 71. He testified that Seale held a sawed-off shotgun on Henry Hezekiah Dee and Charles Eddie Moore as they were whipped after Klansmen picked up the two 19-year-olds and took them to a remote area of the Homochitto National Forest.

Edwards said the Klansmen believed that Dee was a member of the Black Panthers. The Klan had heard rumors that black militants were stockpiling guns for an uprising in Franklin County.

Dee and Moore were beaten 30 to 40 times apiece over 30 minutes with switches about the circumference of a finger, he said.

‘‘I guess we had to give them a spanking to get them to testify where (the guns) were,’’ Edwards said.

Edwards, who is Seale’s cousin, also said it was his idea to pick up Dee and question him about the gun rumors. Dee became a suspect because he had recently spent time in Chicago and often wore a black bandanna.

Of Moore, Edwards said: ‘‘He was just a victim of circumstances. We wasn’t after him.’’

Before Edwards testified, Seale rocked back and forth vigorously in a maroon leather chair at the defense table. But Seale sat still and stared at Edwards during his testimony.

Edwards testified that Clyde Seale, James Ford Seale’s father, was the head of the local Klan and swore Edwards into the white supremacist group.

At one point during his testimony, Edwards described a conversation with Dee that happened during the beating.

‘‘I asked him was he right with the Lord,’’ Edwards said.

Federal prosecutor Paige Fitzgerald asked him why.

‘‘I figured he wasn’t going to make it,’’ Edwards responded.

Fitzgerald then asked him what he thought would happen to Dee and Moore.

‘‘They’d be put away,’’ he said.

When asked to be more specific, he said: ‘‘Well, they’d be killed, I guess.’’

Edwards said that Dee and Moore were ‘‘very much’’ alive the last time he saw them. He testified that James Ford Seale and other Klansmen took the two black teenagers to Clyde Seale’s farm.

Later that day, Clyde Seale dropped Edwards off.

‘‘He told me to go on ahead and keep my mouth shut and everything would be took care of,’’ Edwards said.

Roughly a month to six weeks later, Edwards said he heard James Ford Seale talk about what happened after the young men were taken to the farm.

Edwards said the defendant put duct tape on Dee and Moore, put them in a plastic-lined trunk and with other Klansmen took them across the border into Louisiana, where they were dumped into the Mississippi River still alive.

Edwards said Seale told him at the time that he was concerned about fingerprints being left on the duct tape.

Public defender Kathy Nester said Edwards can’t be believed.

‘‘Frankly, every time he has ever told this story, he has told it differently,’’ Nester told U.S. District Judge Henry T. Wingate.

A sister of Dee, Thelma Collins of Springfield, La., testified earlier Tuesday that her brother was a quiet young man who never made trouble. Wearing a black dress with a white lace collar, Collins kept her composure and occasionally fought back tears. She said her brother had spent a summer with relatives in Illinois and returned with his hair ‘‘processed’’ in a slick style that required lots of care.

‘‘He would put a bandanna around his hair to keep his process in place,’’ she said.

A jury of eight whites and four blacks, with three white alternates, is hearing the trial. Attorneys say the case could last at least a week. Relatives of Seale and the victims have been in the courtroom.

Seale, a former crop-duster from Roxie, has denied belonging to the Klan and pleaded not guilty to the charges when he was arrested in January. Edwards testified that he was a Klan member.

Among other witnesses who have testified in the trial is a retired FBI agent who saw the remains of Dee and More within hours after the partial corpses were pulled from the water.