She said the couple had started dating in late 2017 or early 2018 after meeting through the Philippine Society of Boston College, a student organization dedicated to fostering Filipino culture on campus. Some months into their relationship, Ms. Grasso said, Ms. You discovered that Mr. Urtula had not been truthful about continuing to communicate and socialize with an ex-girlfriend who was also a Boston College student, and the relationship shifted.

From that point on, Ms. Grasso said, Ms. You abused Mr. Urtula psychologically and verbally and frequently threatened to harm or kill herself in order to manipulate him. Witnesses said that Mr. Urtula would often leave social gatherings because she had texted him saying she was going to hurt herself, Ms. Grasso said. If Mr. Urtula did not respond fast enough to her calls or texts, or if he asked for space in an argument or for permission to go to sleep, she would threaten to harm or kill herself, Ms. Grasso said.

By March, Ms. You had isolated Mr. Urtula from his college friends, Ms. Grasso said, requiring him to block their telephone numbers and block them on social media.

Ms. Grasso said Mr. Urtula, who had no documented mental health issues before the relationship, was breaking under the stress.

Late on the night of March 31, Mr. Urtula texted Ms. You, “I asked you to stop so many times,” adding, “I’m breaking down and I’m scared.”

He said he was having “the worst anxiety attack of my life” and was curled in a ball on the couch.

“All the voices are so loud,” he wrote, using an expletive, “and they all have your voice.”

“I want you and the voices to stop,” Mr. Urtula’s texts went on. “To stop telling me how worthless and pathetic I am” and “how much I deserve to die.”