Former "Dynasty" star Catherine Oxenberg says that she felt "horrendous guilt" for introducing her daughter, India, to the group known as "NXIVM."

In an interview that will aired on "Dateline" Monday, Oxenberg told NBC News' Megyn Kelly that she and India had attended classes in 2011 billed as "Executive Success Programs," or ESP, which were run by NXIVM, "just thinking this was a program geared for entrepreneurs," Oxenberg said.

Since Oxenburg’s initial interview with Kelly last fall, a group within NXIVM called "DOS" has been under investigation for allegedly branding women and grooming them as sex slaves for the group’s leader, Keith Raniere.

Raniere and former "Smallville" actress Allison Mack, who was found to be connected to the group, have both been arrested as part of a NXIVM probe by federal prosecutors in New York. They and others charged in the case have denied the accusations and plead not guilty.

After two years of participating in ESP, Catherine stopped taking the classes — but India, 27, only got more involved and even moved from Los Angeles to Albany, New York, to be closer to other followers of the group.

"All of a sudden she's moving to Albany," Oxenberg said. "And I did my darnedest to try to get her involved in other things, to try and redirect her interests, to try and get her other jobs. But nothing worked. I couldn't believe the hold that they had over her."

In addition to allegedly recruiting women to perform sexual acts, the group within NXIVM called "DOS" is accused of branding women with the initials of its leaders.

Oxenberg said that her daughter admitted to having been branded, though India referred to it as "some Latin symbol," and Oxenberg speculated that India was told this, while the branding might have actually been Raniere and Mack's initials.

When Oxenberg asked her daughter why she agreed to this, she says India told her it was "'character building.'"

Oxenberg was eventually texted by a friend of her daughter's, who told her, "'you need to save India,'" the actress recalled.

Oxenberg said she has been fighting to extricate her daughter from NXIVM after educating herself more thoroughly regarding the nature of these types of groups.

"I spoke to numerous experts," Oxenburg said. "And they said, 'Would you stop blaming yourself? These cults are well oiled machines. And India never stood a chance.'"

Oxenberg revealed in the interview that India will be reuniting with her family after her involvement with NXIVM.

"She figured it out. She did it. She's the hero in all of this," Oxenberg said.