Investigators found weapons, several flags and six Klan robes at the campsite, St. Tammany Parish Sheriff Jack Strain said in a news release.
Strain said the woman, whose identity was not released, was recruited over the Internet to participate in the ritual and then return to her home state to find other members for the white supremacist group.
But Strain said the group's leader, Raymond "Chuck" Foster, 44, shot and killed the woman Sunday after a fight broke out when she tried to leave. Foster was charged with second-degree murder and is being held without bond.
Capt. George Bonnett, a spokesman for the sheriff's department, said he didn't know what the initiation involved.
"We haven't completely sorted out if they finished the initiation," he said. "I assume that they had started it, but I don't know if they were finished."
Bonnett said he doesn't know if Foster has an attorney. He also said that in three years with the department, this was the first time he had seen a case involving the KKK.
Seven others - five men and two women from 20 to 30 years old - were charged with obstruction of justice and were held on $500,000 bond at the St. Tammany Parish jail. All eight of the suspects live in neighboring Washington Parish, but Bonnett said he couldn't immediately identify their hometowns.
Authorities said some of the suspects tried to conceal the crime by burning the woman's belongings along with other items at the campsite.
Strain said the woman arrived in the Slidell, La., area last week and was met by two people connected to the Klan group. She was taken over the weekend to the campsite near Sun, La., on the banks of the Pearl River. Sun is about 60 miles north of New Orleans.
Authorities said the group's members called themselves the "Dixie Brotherhood."
"The IQ level of this group is not impressive, to be kind," Strain said, adding, "I can't imagine anyone feeling endangered or at risk by any one of these kooks."
Mark Pitcavage, directive of investigative research for the Anti-Defamation League, said the Dixie Brotherhood appears to be a small, loosely organized group of people.
"This is not what I would call an established Klan group," he said. "The Klan has a pretty high association with violence. Some of these guys are just crooks, sociopaths."