WOONSOCKET — A 17-year-old is being held at the state Training School after he allegedly beat, bit and raped the 2-year-old girl he was babysitting.

The incident occurred between 2 and 3 p.m. Sunday at an apartment in the Borden Street area, according to acting Chief Eric Croce of the Woonsocket Police.

The baby’s mother had left her 17-year-old boyfriend in charge of her toddler at her apartment while she visited a nearby apartment. It was not known what the mother went to the nearby residence for, Croce said.

The police said that the 17-year-old allegedly bit, beat and sexually assaulted the toddler while she was under his care.

When the mother came home, she saw red marks and bruises on her child and asked her boyfriend how the baby got them. She called the police when she doubted his explanations.

Croce said that the police started out investigating whether the teenager had physically abused the child, but during their questioning of him determined that he had also sexually assaulted her.

The toddler was taken to Landmark Medical Center and later transferred to Hasbro Children’s Hospital, where she was held for 72 hours for observation. Doctors found bruises and bite marks on her body, as well as evidence that she had been sexually assaulted, the police said.

The teen, whose name is not being released because he is a juvenile, is charged with first-degree sexual assault by means of forcible rape and first-degree child abuse. He is being held at the Training School pending a probable cause hearing Monday in Family Court.

Croce said he did not know the condition of the child or whether she had been released from the hospital.

The police would not release the police report on the incident.

tpina@projo.com