A 5-month-old baby girl died of apparent drowning in a Capital Hilton Hotel bathtub yesterday, and the child's Swedish mother told police a would-be robber had placed the baby in the tub to enforce his demands for money.

The mystery and confusion surrounding the unusual incident were heightened by the mother's feeble command of English. Police suspended questioning yesterday afternoon until a Swedish interpreter could be summoned.

The woman, identified as Belet Melin, 29, was interviewed for several hours last night with the aid of the interpreter before being dismissed. Also interviewed, police said, was Lars Levin, 29, a gem dealer, also of Sweden, who was described as Melin's fiance. The child was identified as Lilly-Sophie Levin Melin.

Based on initial conversations with the woman, a police spokeswoman released a preliminary account, which left unanswered a number of questions. According to the account, the mother was in her fourth-floor room at the hotel about 12:30 p.m. when she answered a knock at the door and opened it to find an armed man outside.

The police account did not identify the weapon. One source indicated it had been described as a knife.

The man, described as white and between 40 and 45 years old, forced his way into the room and demanded money, the account said.

It was unclear how much-if any-money was in the hotel room. Levin, the gem dealer, reportedly here on a business trip, was not in the room at the time, police said. They said any gems he was keeping at the hotel were in the safe.

The mother, according to the preliminary account, refused the intruder's demands for money and the man took the baby from a crib and carried her into the bathroom. The mother followed. Again the man demanded money, and again, the woman told police, she refused.

Then, police reported, the man turned on the water, placed the baby in the tub and for a third time demanded money. The woman, according to the account, refused this time also.

At this point, according to the initial account, the man left the room, telling the mother to do nothing.

With the child apparently still in the tub, according to the account, the woman left the room to find help, and returned with hotel personnel.

At a 1:30 p.m. news conference, a police spokeswoman said the baby was not taken from the tub "until help arrived." The tub was later described as about one-quarter full of water.

Few other details of the circumstances of the finding of the child were available immediately.

A fire department rescue squad was summoned, and rescue squad personnel took the child to Children's Hospital, where she was pronounced dead on arrival at 1:45 p.m.

Police said death appeared to be due to asphyxiation. They said an autopsy would be conducted.

Police issued a lookout for the intruder described by the mother. No arrest had been made by late in the day.

About 1:30 p.m., when police began the news conference at the hotel, Levin and Melin were escorted from the office of the hotel manager. Reporters were prevented from approaching them. Levin left first.

"Please be careful with my wife," Levin told detectives. "She is very upset." He broke into tears.

While at police headquarters last night, neither Levin nor Melin appeared distraught, one homicide detective said, but both appeared "very much concerned."