Allison Mack has pleaded guilty to blackmailing two women into becoming sex slaves for the leader of the Nxivm sex slave cult.

Mack, 36, sobbed as she admitted her crimes and apologized to the women who prosecutors say were exploited by Keith Raniere and the purported self-help group called NXIVM.

'Through it all, I believed that Keith Raniere's intentions were to help people,' Mack told a judge in federal court in Brooklyn as she pleaded guilty to racketeering charges.

'I was wrong. I now realize that I and others engaged in criminal conduct.'

The Smallville actress was sobbing so much at one point that the judge stopped to offer her tissues.

She had been charged with racketeering, racketeering conspiracy, wire fraud conspiracy forced labor conspiracy, sex trafficking conspiracy , sex trafficking and attempted sex trafficking.

Mack was facing life in prison if convicted on those charges, but will now likely be given a more lenient sentence if she testifies against the other defendants in the case.

Scroll down for video

Allison Mack, 36, pleaded guilty on Monday in a Brooklyn court to blackmailing two women into becoming sex slaves for the leader of the Nxivm sex slave cult

On Monday, Mack said that at Raniere's direction, she obtained compromising information and images of two unidentified women - called 'collateral' within the group - that she threatened to make public if they didn't perform 'so-called acts of love.'

'I must take full responsibility for my conduct. I am very sorry for my role in this case. I am very sorry to my family and to the good people I hurt through my misguided adherence to (Nxivm leader) Keith Raniere’s teachings,' she told the court.

After months of reflection since her arrest, Mack told the court: 'I know I can and will be a better person.'

The plea means Mack will avoid going to trial with Raniere, wealthy heiress Clare Bronfman and another member of Raniere's inner circle, Kathy Russell. All have pleaded not guilty and denied any wrongdoing.

It came as a surprise given lawyers from the Eastern District of New York said they were nearing a deal with Russell and not Mack.

Russell will now be appearing on Monday alongside Keith Raniere and Clare Bronfman for a status hearing and jury selection. Their trial is set to begin later this month.

Bronfman was seen arriving to court on Monday with her lawyer Mark Gergaros.

Mack is now the third defendant to enter a guilty plea, following mother and daughter Nancy and Lauren Salzman.

Court documents obtained by DailyMail.com show that Lauren Salzman appeared before Judge Garaufis last month in an unannounced hearing that was not on the docket.

A redacted transcript from that hearing reveals that Salzman not only informed Judge Garafulis of her plea, but also confessed that she did in fact keep a woman known as Jane Doe 4 captive inside a locked room for two years.

Salzman, 42, also stated that Jane Doe 4 was put to work while enslaved in the room, and revealed that she 'threatened to deport Jane Doe 4 back to Mexico if she did not complete labor requested by myself and others.'

She later admitted to being a member of DOS during the hearing, and confirmed that women were branded with the initials of Keith Raniere and Allison Mack by a doctor who used a cauterizing pen.

Salzman and the other defendants seemed reluctant to take a plea or distance themselves from Raniere for months, but that all changed just a few days before Salzman's hearing when the US Attorney's Office filed new child pornography charges against the Nxivm founder in a superseding indictment.

Mack, 36, wept as she admitted her crimes and apologized to the women who prosecutors say were exploited by Keith Raniere and the purported self-help group called NXIVM

Mack stood close to her attorney as she left Brooklyn Federal Courthouse on Monday after pleading guilty

Those charges have since been drooped and moved to the Northern District of New York.

Lauren Salzman was raised in Nxivm due to her mother's role as a co-founder of the group, and it was her slave Sarah Edmondson that blew the lid on the organization back in a 2017 interview with The New York Times.

Edmondson went into further detail about her time inside the cult on the CBC podcast Surviving Nxivm.

Nancy broke down in tears as she entered a guilty plea to one count of racketeering while apologizing to her daughter and co-defendant, Lauren.

She said that it took a great deal of soul searching to arrive at her decision, and then struggled to gather herself as she stated: 'I am deeply sorry for the trouble I have brought to my daughter.'

Nancy did this without a plea deal in place and said she was eager to begin atoning for hers sins, with her crime carrying a sentence of up to 20 years in prison.

At the same time, attorneys for the US District Court for the Eastern District of New York began laying out their case against the remaining five members of the group, who in addition to NXIVM were also involved in the branded sex cult DOS.

The most shocking claims to emerge out of a memorandum filed in court last month by prosecutors was that Raniere allegedly raped two underage women for years.

Raniere was also in an 'intimate relationship' with billionaire heiress Clare Bronfman, claim the documents, who had previously been funding the legal defense for her five co-defendants but is now distancing herself from the group.

'I am pleading guilty because I am in fact guilty,' said a shockingly frank and emotional Nancy.

'I got involved with NXIVM because I believed we would be helping people, and I still believe some good came out of it.'

The plea means Mack will avoid going to trial with Raniere, wealthy heiress Clare Bronfman and another member of Raniere's inner circle, Kathy Russell. Bronfman (center) arrived at court accompanied by her mother (left) and attorney Mark Gergaos (right) on Monday

Clare Bronfman, pictured arriving at court on Monday, has pleaded not guilty and denied any wrongdoing

On trial: Prosecutors had suggested on Friday that they were having trouble agreeing to a deal with Mack, who is the third defendant to plead guilty (Kathy Russell, who has yet to reach a deal, leaving court on Friday)

The judge scheduled her sentencing for July, and it is unclear if she will now be testifying against her former co-defendants in the case.

'NXIVM's teachings and practices are no more inflammatory than the allegations surrounding the predicate acts and charged offenses themselves, which include keeping a woman in a room for nearly two years, nonconsensual sex, extreme diets and sleep deprivation, sexually explicit photographs and branding of Raniere's initials on women's bodies without their knowledge,' states the new prosecution filing, submitted on Monday.

The memo also details how the government plans to show the ways that the defendants 'protected Raniere and the Enterprise by, among other things, attempting to silence and intimidate DOS slaves and issuing public statements falsely denying Raniere's involvement in DOS.'

One example that is offered involves comment that Bronfman made after she 'received letters from separate DOS victims requesting the return or destruction of collateral, which included descriptions of the collateral, including nude photographs and videos.'

Despite having seen those letters, Bronfman still publicly stated that DOS was a 'sorority' which had 'truly benefited the lives of its members, and does so freely.'

She went on to state: 'I find no fault in a group of women (or men for that matter) freely taking a vow of loyalty and friendship with one another to feel safe while pushing back against the fears that have stifled their personal and professional growth.'

A brief mention is also made of a campaign launched by Bronfman and Raniere to lure former members to Mexico where there were reportedly warrants out for their arrest.

Prosecutors also plan to hone in on the subservient role that woman play and are taught to play in the organization.

'Nxivm's teachings about women's allegedly prideful natures and willingness to 'play the victim,' and the emphasis in Nxivm's teachings on penances and 'ethical breaches,' are interwoven into Jane Doe 4 and the DOS victims' experiences,' states the memo.

'These concepts also appear throughout the documents that will be trial exhibits, including emails between the victims and the defendants.'

It then cites: 'For example, Jane Doe 4 and Raniere exchanged at least 300 emails discussing her supposed 'breach' and approximately 400 emails discussing her acting like a 'victim.''