NEW DELHI — Hundreds of demonstrators besieged New Delhi’s police headquarters on Saturday to protest the kidnapping, rape and torture of a 5-year-old girl last week.

The injured girl was moved Friday evening to New Delhi’s finest public hospital on a gurney covered with stuffed toys, and by Saturday she was alert and in stable condition, according to doctors there. She was being given fluids and intravenous antibiotics to fight a blood infection, the doctors said, and further operations will have to wait until the infection has abated.

Meanwhile, the police arrested a 22-year-old garment worker early Saturday morning in Bihar, said Rajan Bhagat, a Delhi police spokesman. The police identified the suspect as Manoj, who, like many Indians, uses only one name. He had recently married and was tracked down with the help of cellphone records in the town where his in-laws live, according to Indian news reports.

The suspect had an apartment in New Delhi in the same building as the girl, whom he is accused of abducting, raping and torturing last Sunday night. The Times of India reported that he told the police he fled his apartment shortly thereafter because he believed that the girl had died. The girl’s parents discovered her on Wednesday in the man’s apartment.