It began with a crush, police said, and turned into one of the most shocking crimes in Milwaukee's long, violent summer: An 11-year-old girl was sexually assaulted by as many as 20 boys while a 16-year-old girl she was romantically interested in watched and coached her.

The 16-year-old and a 15-year-old boy have been charged in juvenile court in the alleged attack, which authorities said took place Monday in a house on the city's north side. The teenage girl's 40-year-old uncle might also be charged, authorities said.

The youth's names were not released because of their ages.

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Investigators are still trying to identify and locate the boys who were in the house. At least another male was arrested Thursday, police spokeswoman Anne E. Schwartz said Friday.

"We're dealing with a lot of nicknames, so we're trying to track down these people," said prosecutor Matthew Torbenson.

The 11-year-old girl told police she was interested in the teenage girl, who looked and dressed like a boy, authorities said in court records. She and two friends went to the teen's house, where the child performed oral sex on three teenage boys, the court records said.

The teenage girl's 40-year-old uncle admitted he also had sex with the 11-year-old and told police that his niece was coaching the child, the records said.

The 11-year-old told police she then went to the basement, where there were about 15 males and "began to choose who she wanted to perform oral sex on," the records said.

The teenage girl told police that the 11-year-old had told her she wanted to perform oral sex on the boys in the house, according to court records. The 16-year-old denied encouraging her.

The teenage girl and the 15-year-old boy were charged with being a party to sexual assault. Torbenson said he will probably seek to have them tried as adults.

The reported attack punctuated Milwaukee's felonious summer, which started with a Memorial Day weekend in which 28 people were shot. Though homicide numbers are lower than 2005, assaults are up by 22 percent and robberies by 36 percent, Schwartz said.

Several mob attacks have taken place in Milwaukee's inner city in recent years. In 2002, more than a dozen people, mostly boys, chased a man through the streets and beat him to death with shovel handles, rakes and tree limbs.

A mentally ill man died after being beaten and robbed by a group in 2004. Four days after that attack, a 14-year-old boy was kicked, punched and hit on the head with a piece of lumber after he exchanged words with a girl. He was in a coma for two weeks. Also that summer, four brothers were beaten by a group armed with bats, bottles, sticks and socks stuffed with canned food.

Mayor Tom Barrett described the latest alleged crimes as disgusting and deeply troubling.

"When you have people working in concert and no one in the group is showing conscience, that's a real problem," he said.

"It almost leaves me speechless," said Barbara Nuell-Moore, director of the neighborhood-improvement group Project Respect. "It is just senseless acts of violence. It is inhumane. It is embarrassing to the city of Milwaukee and its people. ... There should be outrage."

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