Casandra "Cassie" Ventura Fine, who testified against her ex-boyfriend Sean "Diddy Combs during his landmark federal sex-crimes trial, is speaking out against the music mogul's potential release from prison ahead of his sentencing hearing.

In a letter to U.S. District Court Judge Arun Subramanian filed Tuesday, Sept. 30, Ventura Fine opened up about the psychological toll of her decadelong relationship with the disgraced rapper, as well as shared her concerns about Combs' custody status.

"I still have nightmares and flashbacks on a regular, everyday basis, and continue to require psychological care to cope with my past," Ventura Fine wrote, according to court documents obtained by USA TODAY. "My worries that Sean Combs or his associates will come after me and my family is my reality."

Ventura Fine revealed that she's maintained a low profile since Combs' trial, which concluded in July and saw the Grammy-winning rapper receive a split verdict, convicted on two counts of transportation to engage in prostitution but acquitted on the more serious charges of racketeering and sex trafficking. The one-time R&B star added that she and her family have also moved out of the New York area as a safety precaution.

"I am so scared that if he walks free, his first actions will be swift retribution toward me and others who spoke up about his abuse at trial," Ventura Fine continued. "As much progress as I have made in recovering from his abuse, I remain very much afraid of what he is capable of and the malice he undoubtedly harbors toward me for having the bravery to tell the truth."

Ventura Fine, who met Combs when she was 19 as an aspiring singer, testified during Combs' monthslong federal trial, peeling back the curtain on years of alleged physical and sexual abuse, which included participating in several of Combs' reported "freak-off" sex parties. Her bombshell testimony came nearly two years after Ventura Fine filed a civil lawsuit against Combs in November 2023, which the pair resolved in 24 hours with a $20 million settlement.

Combs, who is expected to be sentenced on Friday, Oct. 3, remains in custody at Brooklyn's Metropolitan Detention Center after repeated attempts at bail, all of which have been denied.

Ventura Fine's statements against Combs come after several of Combs' loved ones and associates, including City Girls rapper Yung Miami and producer Dallas Austin, wrote letters of support to Subramanian requesting "leniency" for the hip-hop mogul's sentence.

Cassie talks suicidal thoughts, healing journey after Diddy abuse

In her Sept. 30 letter to Judge Subramanian, Ventura Fine rehashed the repeated abuse she allegedly suffered at the hands of Combs, which included performing numerous sex acts with male sex workers, harrowing physical violence and substance abuse.

"While the defense attorneys at trial suggested that my time with Combs was akin to a 'great modern love story,' nothing could be further from the truth," Ventura Fine wrote. "Nothing about this story is great, modern, or loving — this was a horrific decade of my life stained by abuse, violence, forced sex and degradation."

The "Me & U" songstress said the mental health impact of Combs' purported abuse drove her to thoughts of suicide, adding that she was able to navigate the distress thanks to "my family’s intervention and urging that I seek professional care." Ventura Fine is married to personal trainer Alex Fine; the couple shares three children.

"I have been to rehab and have taken part in dozens of types of therapy modalities to confront, compartmentalize and cope with the horrific memories of sexual and emotional abuse I endured for nearly 10 years," Ventura Fine concluded. "While what he did to me is always present, I am slowly learning how to live my life free of the fear and horrors I endured, and in doing so am fully devoted to my husband and my children."

Cassie claims Diddy is not 'a changed man' after trial

While Ventura Fine has hope for her future, she can't say the same about her ex, Combs.

"His defense attorneys claim he is a changed man, and he wants to mentor abusers. I know firsthand what real mentorship means, and this disgusts me; he is not being truthful," Ventura Fine wrote in her letter to Subramanian.

"I know that who he was to me — the manipulator, the aggressor, the abuser, the trafficker — is who he is as a human," she continued. "He has no interest in changing or becoming better. He will always be the same cruel, power-hungry, manipulative man that he is."

Ventura Fine also criticized Combs' about-face in acknowledging his physical abuse after the leak of surveillance footage showing him attacking Ventura Fine at a Los Angeles-area hotel in 2016. Combs issued a video apology on social media after the footage was released by CNN in May 2024.

"When I came out with my allegations in my civil case, he flatly denied them again and again," Ventura Fine said. "It was only after actual video footage corroborated the exact words in my civil complaint that he issued an insincere apology on the internet. Thanks to the footage and my testimony, this is also something he will forever be associated with."

Cassie asks judge to consider Diddy's history of 'abuse and control' ahead of sentencing

For Ventura Fine, the pursuit of justice has come at a cost.

"For four days in May, while nine months pregnant with my son, I testified in front of a packed courtroom about the most traumatic and horrifying chapter in my life," Ventura Fine wrote in her Sept. 30 letter. "I testified that from age 19, Sean Combs used violence, threats, substances and control over my career to trap me in over a decade of abuse."

She added: "Reliving in detail the events and truths described throughout the trial and this letter causes me tremendous emotional pain. I am trying with all that I am to move on."

Ventura Fine's testimony during Combs' trial was often highly emotional, with the singer breaking down in tears as she recalled the trauma she said she suffered in her relationship with the Bad Boy Records founder. As Subramanian contemplates Combs' sentencing, Ventura Fine asked the New York judge to consider "the many lives that Sean Combs has upended with his abuse and control."

"For over a decade, Sean Combs made me feel powerless and unimportant, but my experience was real, horrific and deserves to be considered," Ventura Fine concluded. "While the jury did not seem to understand or believe that I engaged in freak offs because of the force and coercion the defendant used against me, I know that is the truth, and his sentence should reflect the reality of the evidence and my lived experience as a victim."

If you or someone you know may be struggling with suicidal thoughts, you can call the U.S. National Suicide Prevention Lifeline at 988 any time, day or night, or chat online.

If you or someone you know has experienced sexual violence, RAINN’s National Sexual Assault Hotline offers free, confidential, 24/7 support to survivors and their loved ones in English and Spanish at: 800.656.HOPE (4673) and Hotline.RAINN.org and en Español RAINN.org/es.

If you or someone you know is a victim of domestic violence, call the National Domestic Violence Hotline at 1-800-799-7233 or text "START" to 88788.

Contributing: USA TODAY staff reports

This article originally appeared on USA TODAY: Cassie reveals she has recurring 'nightmares' in Diddy sentencing letter

Reporting by Edward Segarra, USA TODAY / USA TODAY

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