A 26-year-old Anne Arundel County woman was charged yesterday with first-degree murder in the death of a 3 1/2-month-old boy, who police said was drowned, scalded and painted with fingernail polish.

Patricia Spriuill of Severn, who was baby-sitting with the child, was arrested early yesterday morning after police were summoned to the three-bedroom town house she shared with the boy's mother, a woman and nine children, police spokesman Dick Molloy said.

Molloy said Spriuill told police the baby woke up crying early yesterday morning and she was unable to stop him.

Molloy said the baby, identified as Jonar Gilliam, had stripes painted on him with fingernail polish and had been immersed in a tub of water until he was "partially drowned." Scalding water was then poured over him, Molloy said, and he was painted again with fingernail polish.

The boy was not breathing when paramedics arrived, and he was pronounced dead on arrival at North Arundel Hospital. Cause of death was listed as "a combination of drowning, scalding and shock," Molloy said.

Police and paramedics were called to the scene after Spriuill hitchhiked about two miles to the noncommissioned officers' club at Fort Meade, where she alerted the boy's mother, Chantell Ransom, to the emergency at home, Molloy said.

Ransom, her boyfriend, and Spriuill returned to the house and notified authorities, Molloy said. Ransom has two other children, aged 2 and 3, police said.

Spriuill, who has three children, aged 3, 4 and 7, was being held without bail at the county detention center, police said. None of the other children in the house was hurt.

Molloy said that when telling her story to police, Spriuill "seemed very rational, never got excited, and there was no evidence of drugs or alcohol."