Prosecutors in Massachusetts laid out a disturbing case against a young woman accused of urging her boyfriend to kill himself through a barrage of text messages as she was arraigned in Boston Friday morning. Inyoung You, 21, is charged with involuntary manslaughter in the death of 22-year-old Alexander Urtula, who leapt to his death from a Roxbury parking garage in May hours before his Boston College graduation ceremony.

Inyoung You in Suffolk Superior Court, Nov. 22, 2019. WBZ-TV

You, who had attended Boston College with Urtula, walked into Suffolk Superior Court 12 minutes late and did not speak during the hearing in which her lawyer Steven Kim entered a not guilty plea on her behalf. You showed no emotion as Suffolk County Assistant District Attorney Caitlin Grasso read dozens of expletive-filled text messages in which You repeatedly told Urtula to "go kill yourself," berated him as a "worthless piece of s---" and threatened to harm or kill herself if Urtula didn't comply with her demands.

Grasso said You "overwhelmed Mr. Urtula's will to live" with consistent and repeated psychological abuse, giving rise to a "life-threatening condition." Grasso also said You failed to act to save his life even though she was with him on the roof of the parking lot prior to his suicide.

Grasso said the nearly 74,000 text messages the couple exchanged in the two months prior to Urtula's May 20 suicide demonstrated their "power dynamic," and said Urtula was You's "slave" and that he "ceded his autonomy" to You as a condition of the relationship.

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"You own me, all of me, only you. You have complete control of me emotionally and physically. You dictate my happiness," Urtula wrote to You in one message. "You owning all of me includes everything, what I think, what I feel, you own all of that. All my history, everything. Anything you want, I want to give it to you."

In a statement, however, Kim said the district attorney's office has "branded an emotionally fragile young woman a monster to the entire world, further traumatizing her. It also happens not to be true."

"When the facts come out it will be clear – these were two emotionally needy young adults whose relationship had become a toxic blend of need, anger, fear and love," the statement said. "They simultaneously faced the everyday pressures all post-adolescents encounter from family, friends, social media, college life, and the things young people try to navigate every day. And they lived their lives on their phones in a way that is hard for many of us to understand."

Alexander Urtula and Inyoung You Urtula family via Suffolk DA's Office/CBS Boston

He called Urtula's death a tragedy, but said there's no way to know what would cause someone to commit suicide. He said You is among those mourning his loss.

"Further punishing a young woman who loved him only compounds the tragedy and tarnishes the memory of that young man," the statement said.

Grasso, however, said said the state would present the texts, witness statements and Urtula's handwritten journal entries to show You was "physically, verbally and psychologically abusive" during the course of the couple's 18-month relationship. Grasso described a "staggering" cycle during which a quarrel would give rise to thousands of texts per day, followed by a few days with "'only hundreds" exchanged. The couple was also constantly on FaceTime, Grasso said.

You was enraged when she discovered Urtula was continuing to communicate with an ex-girlfriend, another Boston College student, Grasso said. Grasso said the alleged abuse "intensified" in the days and hours before his suicide. By that time, she said, You had isolated Urtula from his friends at Boston College, forcing him to block their phone and social media communications. A text exchange four days before his suicide showed You was livid that Urtula would see the friends, including the ex-girlfriend, at the graduation ceremony.

"You f--- piece of s---. Go f---die in hell. You deserve to go kill yourself. There's a main ceremony with all of you and you lie and say you won't see them at all? Can you go f---kill yourself and leave me the f---alone. And if you don't die, I'm going to f---- kill myself."

Another text that day read: "I want to bash your head against the wall. Can you go f---hit your head on the f----sink repeatedly? You are literally a piece of s----. You should go f----- die, or else I'm going to go slit my wrists again. How f---- idiotic you are like, baffles me."

You was "constantly driving" talk of suicide in the texts, both threatening to take her own life and urging Urtula to take his, Grasso said. In one text exchange, Urtula begs You not to harm herself, offering to take his own life to stop her.

"Inyoung please, I'll give you whatever you want. I'll leave this f----- earth. I'll go die like you want. I'll erase myself from this world. I don't have anything anymore if I don't have you."

Grasso said friends described Urtula as "driven, strong-willed and a leader" before he began dating You at the end of 2017, when the two met through a club that promotes Filipino culture on the school's Brighton campus. He previously had no history of depression or threatening suicide, but friends noticed a stark difference in his behavior during the relationship, Grasso said.

At one point in early December, Urtula texted two of his friends: "I'm worried. I need help. I can't do this alone," prompting one friend to contact an emergency services hotline about You's behavior.

Friends told prosecutors Urtula felt "trapped" in the relationship, Grasso said.

"The reason he didn't feel comfortable ending the relationship was because he knew if he did that, she would do something drastic like hurt or kill herself," one friend said, according to Grasso.

Grasso also quoted from Urtula's handwritten journals, in which he wrote, "She attacks my self-worth. Whenever we argue it always reverts back to the past, how I lied and hurt her before, and how she doesn't believe it won't happen again. Then when I agree to end it because she says she's done with me because I'm a 'horrible r----- f---up that's just burdening everyone's life' she in turn threatens to kill herself because of me."

The morning of Urtula's suicide, Grasso said Urtula had spent the night at You's dorm. Rather than meeting his family for his graduation ceremony as planned, he took an Uber to the Roxbury MBTA parking garage, arriving around 7:30 a.m. He then repeatedly texted You and his brother that he was planning on killing himself, Grasso said. You tracked his location using his phone and arrived at the garage about an hour later. Minutes afterward, Urtula took his own life.

Grasso said You knew his location for nearly an hour but never called authorities to report that he planned on killing himself. But earlier this week, a public relations firm representing You released different text messages to the Boston Globe, claiming You had tried to stop Urtula from commiting suicide that morning.

In those text messages, You repeatedly asks Urtula where he is, and repeatedly tells him to "stop."

"ALEX. WHAT ARE YOU F---- DOING. IF U F----- LOVE ME STOP. IF U EVER F---- LOVED ME STOP," You wrote.

Kim, You's lawyer, accused the district attorney's office of "cherry picking" from the massive amount of text messages and creating a "media storm" that he believes is tainting the jury pool.

"I've never in my entire career seen such unjust and callous behavior by a district attorney in what I can only conclude is the cheap pursuit of headlines," Kim told reporters after the hearing, according to CBS Boston.

You faces the same charge as Michelle Carter, the young woman who was convicted in the same state of coercing her boyfriend's suicide via text message. "48 Hours" investigated the case in the episode, Death by Text: The case against Michelle Carter.

Prosecutors and You's defense agreed to set her bail at $5,000 because she had no prior offenses and had returned from South Korea voluntarily to face the charges. In a statement, her attorney emphasized she is an American citizen who grew up in Washington state. He said her parents are preparing to re-locate from South Korea for the trial proceedings.

Suffolk County District Attorney Rachael Rollins said in a statement that Urtula's family has "endured an unimaginable amount of pain" and asked the media to respect their privacy.

"We will honor Alexander and his legacy by holding the defendant accountable for her relentless, reckless, abusive and criminal behavior," the statement said. "This process will be long and difficult, but we will be there with the Urtula family each step of the way, remembering the best parts of Alexander."

You posted bail after she was led away handcuffed following the hearing, showing no emotion. She was ordered to surrender her passport and remain in Massachusetts until her November 2020 trial.

Cassandra Gauthier and Mola Lenghi contributed to this report.