BOSTON (CBS) — The mother of a 2-year-old girl whose body washed up on Deer Island two years ago said Monday that she now realizes she “made a mistake” in not alerting authorities about her daughter’s murder.

Rachelle Bond wept on the witness stand Monday morning when asked to identify her daughter, Bella Bond, in a photo–and again later when her voice was played to the court in a voicemail message.

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“She was always happy,” she said through tears, about the girl once known by the public only as “Baby Doe.” “We were always happy.”

Rachelle Bond continued her testimony in court Monday morning. (WBZ-TV)

Rachelle testified last week that she saw her ex-boyfriend, Michael McCarthy, kill Bella in 2015. She told the court Monday about the moment she found out, while watching the news, that her daughter’s body had been found.

McCarthy, 37, is charged with first-degree murder in Bella’s death. Prosecutors say he struck and killed her because he was obsessed with the occult and believed she was a “demon.”  The defense, however, claims Rachelle Bond killed her daughter.

Michael McCarthy watches Rachelle Bond testify against him in court Monday. (WBZ-TV)

Rachelle described what a typical day was like with Bella–before McCarthy moved in.

She said she initially thought she and her daughter could be happy living with McCarthy. A photo showing the three of them with a small dog was shown on court monitors.

Bella Bond, Rachelle Bond, and Michael McCarthy. (WBZ-TV)

In her testimony on Friday, Rachelle told the court about the night Bella died. She said she saw McCarthy go into Bella’s room and punch her in the stomach because she didn’t want to go to bed.

“What the (expletive) did you do?” Bond said she yelled to McCarthy.

After Bella was killed, Rachelle said McCarthy put her body into a duffel bag with weights and threw it into Boston Harbor. She admits to helping him.

Rachelle said Tuesday that she didn’t alert authorities about her daughter’s death because McCarthy had threatened to kill her–a threat she took seriously because, she said, he had killed Bella.

She also said McCarthy told her nobody would believe her because of her past troubles with police and the Department of Children and Families, which she admitted in court last week had already taken two of her children due to neglect.

“I just felt like I would be at fault,” Rachelle said. “He drilled it into me … he’d constantly say nobody’s gonna believe you.”

Rachelle, who detailed her descent into drug use in her testimony Friday, said she was using her disability checks to purchase heroin and inject it up to seven times a day to deal with Bella’s death.

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When she was in court after Bella’s death on an unrelated matter, texts shown in court show McCarthy urging Rachelle not to bring up Bella because “We don’t want to get DSS involved.”

She said McCarthy got her into Alex Jones conspiracy theories in the time after the murder.

Rachelle said that Joe Amoroso, Bella’s biological father, visited in September looking for the daughter he had never even met.

“I told him she was with her godparents at the time,” Rachelle said.

McCarthy’s lawyer, Jonathan Shapiro, focused on this and other instances of Rachelle telling others that Bella was still alive during cross-examination Monday afternoon.

Under questioning from Shapiro, Rachelle admitted she should have told authorities about Bella’s murder sooner.

“I took blame for my part of it,” she said. “I am ashamed for it, for everything that happened after. I made a mistake.”

When Bella’s body was found by a woman walking her dog on a Deer Island beach in 2015, authorities issued a computer-generated image of the then-unidentified girl, who came to be known as “Baby Doe” by the millions who shared those photos on social media.

Rachelle Bond’s daughter Bella and the image of Baby Doe issed by police. (Facebook photo and State Police image)

The girl was later identified as Bella after, prosecutors say, Rachelle told a former friend of McCarthy’s that he had killed the girl.

Rachelle told the court that she told Michael Sprinsky, who had lived with the couple before Bella’s death, that Bella had been taken by DCF. But when Sprinsky told her she could get her daughter back, she confessed to him that she couldn’t–because McCarthy had killed her.

She said she told Sprinsky because she knew he would believe her.

She said police came to her house, but she left through the back window–because, she said, she wanted to tell Amoroso everything first. She told police she first saw the “Baby Doe” photos on TV at Amoroso’s parents’ house.

When she saw the police photo of Bella’s zebra-print blanket, she said she fell to her knees, crying.

Not long after, she was interviewed and arrested by police, who charged her with being an accessory to murder after the fact.

Shapiro also grilled Rachelle on inconsistencies between her initial interview with those officers and her testimony on Friday. Parts of that initial interview were shown in court Monday afternoon.

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Rachelle agreed to testify for the prosecution in exchange for a guilty plea in the case, and could walk free on time served at the end of the trial. She pleaded guilty to helping dispose of Bella’s body.