A trio of runaway teenage girls were beaten, raped, and forced to prostitute themselves in parked cars, hot-sheet motel rooms, and other desolate commercial areas around Queens by a man known by the nickname “Hobbes,” the authorities said yesterday.

The runaways, aged 13, 15, and 16, were forced to work seven days a week and expected to perform sexual acts with an average of seven men a night, prosecutors said. They charged about $50 for oral sex and $100 for intercourse, and were not given condoms or money to purchase them.

Both the man alleged to have pushed the teens into prostitution, 30-year-old Barrington Heffenden, along with one of the teens, Angela Perez, 16, were arrested on Thursday and charged with kidnapping and promoting prostitution, among other crimes. Ms. Perez is alleged to have helped Mr. Heffenden recruit a 15-year-old girl, a recent runaway from Suffolk County, and a friend of hers from school.

If convicted, Mr. Heffenden and Ms. Perez stand to face a maximum sentence of 25 years in prison. Court-appointed attorneys for Mr. Heffenden and Ms. Perez could not be reached early yesterday evening.

According to prosecutors, police detectives first became aware of the underage prostitution ring when the 15-year-old teenage girl living with Mr. Heffenden escaped from his house late Wednesday night and rode the subway into Brooklyn, where she alerted authorities.

Prosecutors said the 15-year-old told detectives she had come to work as Mr. Heffenden’s prostitute through Ms. Perez, whom she had known through school. After running away from her home in Suffolk County on January 5, Ms. Perez invited her to stay with Mr. Heffenden. He raped her that night in the house, prosecutors said, and then threatened her with violence if she chose not to work for him as a prostitute the next day.

Prosecutors said Mr. Heffenden also raped the 13-year-old girl, a runaway from the Bronx, and participated in sexual acts with her multiple times at his home and also at his mother’s apartment on Linden Boulevard.

In exchange for their services, which law enforcement sources estimate brought Mr. Heffenden more than $50,000 since September 2004, the underage teenagers were given alcohol, along with drugs such as cocaine and marijuana.

Most times, a client would drive to Mr. Heffenden’s house and take the girls to locations like nearby houses, motel rooms, or into cars, prosecutors said. Other times, they would solicit on the street. After finishing their work, which typically lasted from between 2 a.m. and 7 a.m., the teenage girls slept on couches in a room in Mr. Heffenden’s home that one investigator called “a festering sinkhole,” according to one law enforcement source.