A 10-month-old girl remained hospitalized in grave condition yesterday, the result, police said, of a horrific assault by the boyfriend of the child's mother.

The suspect, Clinton Smith, 30, of Herman Street in Troy Hill, was held in the Allegheny County Jail on charges of aggravated assault, reckless endangerment, rape, involuntary deviate sexual intercourse and child endangerment.

A preliminary hearing is scheduled for Wednesday at 12:30 p.m. in City Court.

The baby's mother told police that she went to work around 10:30 a.m. Thursday, leaving the infant in the care of Mr. Smith.

The mother said the child was fine when she was left with Mr. Smith, a police affidavit said.

The mother said she returned home at 9:30 p.m. and found her daughter unresponsive and bruised.

Ten minutes later, police and medics arrived, and the baby, with no pulse and not breathing, was taken to a hospital.

Doctors told police the child had not been breathing for at least half an hour when she arrived in the emergency room.

Eventually, doctors were able to obtain a pulse, but the baby had not resumed breathing on her own yesterday, police said.

A spokesman at UPMC Children's Hospital said late yesterday the baby's condition had not changed.

The police affidavit said the baby suffered bruises on her face, arms and legs, as well as a bite mark on her chest. Doctors told police the baby had been sexually assaulted.

Under questioning by police, Mr. Smith said he did not know how the child suffered the injuries. He said he and his 2-year-old son were home alone with the baby the entire time her mother was at work.