METHUEN — For years, Emilio Delarosa had threatened to kill Wanda Rosa.

Less than a month after their son was born in November 2011, he told her “this child is going to be left without a mom.’’ Five months later, he put a gun to her head and smothered her until she saw black, according to court documents.

Delarosa was sentenced to four years in prison for the attack, and before he was released in January, Rosa won a restraining order against him. But she wanted their son to have a relationship with his father, and in July the order was modified at her request to allow him to visit, so they “could do things together as a family.’’

On Tuesday, authorities charged Delarosa, 32, with murdering Rosa, who was found unresponsive Monday in her Methuen apartment.

Delarosa remained at large. A warrant for his arrest was issued on Tuesday, Methuen Police Sergeant Eric Ferreira said.

Investigators believe Delarosa killed his former girlfriend while their 4-year-old son was in the home, then dropped the boy off at a relative’s house before fleeing.

“This happened to her because of her being such a loving person, such a forgiving person,’’ said Edinson Corporan, who had been close friends with Rosa for 10 years. “She was trying to have a daddy figure there for her son.’’

Court records document years of abuse. Rosa and Delarosa began dating in late 2009 or early 2010, and before long he had taken her cell phone, made her quit her job, and banned her from Facebook.

By April 2010, he smashed her face into his dashboard after picking her up from a bachelorette party, the records state.

In the May 2012 attack that sent Delarosa to prison, he told Rosa that he planned to go to her mother’s house and shoot everyone there. He grabbed her by the hair, pointed a gun at her head, and choked her until she almost passed out, according to court documents.

At one point during the attack, Delarosa ordered her to open a bag, where she found duct tape, rope, and zip ties, the documents state. To placate him, she promised to move to Florida with him and got into a car with him and their son.

As they drove south on Interstate 95, Rosa escaped at a service area in New Jersey, where workers hid her and called police, according to the documents.

Delarosa pleaded guilty to charges of attempted murder, kidnapping, and assault and battery causing serious bodily injury. He was sentenced to four years in prison.

Months before Delarosa was released, Rosa brought their son to visit him in prison. She told Delarosa he could have a relationship with the boy as long as he did not expect one with her. She was seeing someone, she told him.

In a chilling response, Delarosa said he regretted “not finishing what he started,’’ records stated.

Rosa sought a restraining order after that conversation in October 2015, the same order a judge modified in July at her request.

Women who share children with their abusers face an excruciating dilemma, advocates say.

“This is the complexity of domestic violence and the cycle of abuse,’’ said Arelis Huertas, who oversees domestic violence and sexual assault programs at the YWCA of Greater Lawrence. “Many survivors say, ‘He’s a great father, he was only abusive toward me.’ You have children that want to see their parents.’’

Huertas said she urges women not to modify restraining orders to allow contact. When an abuser is allowed to visit, it is often only a matter of time before the violence begins again, she said.

Domestic abusers will often use their children to gain reentry into their victims’ lives, she said.

“A lot of the times, [mothers who survive abuse] want to hope, at least for the child’s sake,’’ Huertas said. “They don’t want the child to grow up without a father figure.’’

Corporan, Rosa’s longtime friend, said Rosa had spoken of her fear of Delarosa and told him about the 2012 attack.

“The guy was gonna kill me; I just got lucky,’’ he said, recalling their conversation.

Rosa was a devoted mother, he said, and had hoped to start an online business. “She was trying to do something in her life,’’ he said.

On Tuesday, mourners left candles and flowers outside Rosa’s apartment. Two Methuen police detectives visited the development to speak with residents. Some recalled Delarosa coming to visit, but said he never spoke to anyone.

Maria Gesualdo said she spent Sunday night with her mother and grandmother, who live next to Rosa’s apartment. Around 3 Monday morning, Gesualdo said she heard Rosa’s son crying.

“Then,’’ she said, “everything was quiet.’’

John R. Ellement and Kathy McCabe of the Globe staff contributed to this report. Laura Crimaldi can be reached at laura.crimaldi@globe.com. Evan Allen can be reached at evan.allen@globe.com.