A computer-generated image of the girl was shared by millions on social media by authorities trying to determine her identity.
The widely shared image showed a chubby-cheeked, brown-eyed girl. Bella's body was found inside a trash bag on Deer Island in June 2015.
The jury started deliberating June 20. It found him guilty of second-degree murder.
"Second-degree murder means justice for Bella".
McCarthy, 37, will be sentenced Wednesday, prosecutors said.More news: Avis teams up with Waymo on self-driving car program
"An innocent life was not merely snuffed out, but callously discarded", Conley said.
Defense attorney Jonathan Shapiro focused on trying to undermine Bond's testimony.
Bond testified during the trial, a requirement of her plea agreement, and said that she saw McCarthy punch the child in the stomach. The child's mother, Rachelle Bond, pleaded guilty earlier this year to being an accessory after the fact and became the prosecution's star witness.
Rachelle Bond has been in prison for the last two years.
"Today, there is no justice for Bella Bond", Shapiro said. During her time on the witness stand, she sparred with McCarthy's attorney, who noted inconsistencies in what she told police in September 2015 and her testimony. When the girl stopped screaming, Bond testified that she saw that the girl's head appeared to be swollen and her face was gray.More news: Rockets' Eric Gordon wins NBA Sixth Man of the Year
He said McCarthy had been obsessed with the occult for years. A friend testified that McCarthy would lock the toddler in a closet to discipline her. Prosecutors alleged that McCarthy murdered Bella because he thought she was possessed by evil spirits.
During the trial, McCarthy's attorney painted Bond as Bella's real killer, calling her a "monster". "But at the same time, that doesn't make her a murderer".
Conley said that it was clear Bond loved her little girl, but let her down through her drug use. She claimed McCarthy threatened to kill her.
"Rachelle Bond's testimony was clearly valuable and credible because it was corroborated by forensic evidence that she did not know we would obtain", Conley said, citing cell phone records that corroborated her testimony about the couple's whereabouts in the days following her death. He called her 'honey, ' 'good girl, ' " the Boston Globe reported. McCarthy was convicted Monday of sec.
The man accused of killing Bella Bond is guilty of murder in the second degree, a jury decided Monday morning. Defendant Michael P. McCarthy, center, reacts after a guilty of second degree murder verdict against him at Suffolk Superior Court on Monday, June 26, 2017.More news: House panel wants formal response from Trump on Comey tapes
Assistant District Attorney Deakin emphasized to the jury that they must not judge McCarthy, Bond and the other individuals involved in the case as a group of addicts. Michael McCarthy has however escaped conviction on the more serious charge of first-degree murder for allegedly punching 2 and a half year old Bell Bond to death.