Robert Davidson, a 24-year-old father from Rockville, Maryland, pleaded guilty Monday to sexually abusing and killing his 10-week-old daughter last year. The autopsy of his daughter, Aleah Thompson, showed she had suffered from a broken collarbone and 34 fractured ribs, the Washington Post reported.

Assistant State’s Attorney Mary Herdman said in court that additional injuries to the infant's eyes, head and spine indicated that the baby also suffered physical abuse in the first two weeks of her life before her death on June 23, 2015.

The fatal injuries occurred when Davidson was left alone to babysit the infant while his girlfriend, Lorena Thompson, was at work. During his initial interview with police on June 23, Davidson said he was playing video games when he heard noises indicating his baby was having trouble breathing from the bedroom.

When he went to check on her, Davidson found the 10-week-old unresponsive and unconscious, prompting him to call 911 for help. Davidson was performing CPR on the infant when police and medics arrived at the scene. Aleah died in the hospital three days later.

Herdman said Davidson later admitted to the police that he had repeatedly dropped and shaken the infant after finding her unconscious. Davidson also said his daughter had fallen off the couch.

It's unclear how he sexually abused his daughter, the New York Daily News reported Tuesday. Ronald Gottlieb, Davidson’s attorney, said in court the father was “trying to remove mucus and other substances” from his daughter.

“He never admitted to doing it for a sexual gratification, but the actual act itself he has admitted to,” said Gottlieb in court.

Lorena Thompson was also charged in the case and pleaded guilty to neglect of a minor on July 22. She told investigators she had previously noticed bruises on Aleah after being in her boyfriend’s care, but neither alerted the authorities nor sought out medial attention.

Neglect is the most prevalent form of child abuse in the U.S., according to the National Children’s Alliance, a children’s advocacy center based in Washington D.C.. Of the 702,000 children who were maltreated or abused in the U.S. in 2014, about 80 percent suffered neglect, 18 percent experienced physical abuse and 9 percent witnessed sexual abuse.

More than 700,000 children were abused in the U.S. every year, according to data from the U.S. Department of Health and Human Services from 2014. Roughly 1,564 children died because of abuse or neglect in the U.S. in 2014.