By David DeKok

HARRISBURG, Pa. (Reuters) - A young mother accused of dropping her toddler into eastern Pennsylvania's Lehigh River before jumping in herself was charged on Monday with criminal homicide after the boy died of his injuries.

The charges against Johnesha Monae Perry, 19, of Allentown, were upgraded from attempted homicide after her son, Zymeir Perry, aged 20 months, died on Saturday after the withdrawal of life support, Lehigh County District Attorney Jim Martin said in a press release.

An autopsy on Monday confirmed that the boy’s death was related to blunt force trauma from the 52-foot fall.

Perry took her son onto the Hamilton Street Bridge in a stroller on May 3, Allentown police said in court papers. She stopped halfway across, sat the boy on the bridge railing, kissed him, and pushed him over the side, according to police.

Perry then jumped off the bridge herself. While injured, she was able to walk out of the river, police said.

Police officers rescued the boy from the river after he had floated several hundred feet downstream.

Although no pulse was detected for him at the scene, medical personnel at Lehigh Valley Hospital were able to restore a heartbeat.

The child's condition deteriorated over the next days, according to court papers. On Saturday, he was declared brain dead and life support was removed.

Police said Perry told them that she threw the baby off the bridge to kill him, according to court papers.

(Editing by Barbara Goldberg and Peter Cooney)