The two girls were runaways, 15 and 17, who had left their homes in Eau Claire, Wis., in early July and found their way to the Twin Cities. To the people who took them in, the girls were moneymakers. They were plied with drugs, dressed in lingerie and advertised for sex on the website Backpage.com.

Minneapolis police say the girls were repeatedly prostituted over several weeks before investigators traced a cellphone and found them in a home in north Minneapolis on Saturday. They also arrested a woman, who admitted the home at 2722 Oliver Av. N. was used for prostitution after a pimp and drug dealer she knew had brought the girls there, according to the criminal complaint.

Meranda L. Warborg, 29, was in the Hennepin County jail after being charged with two counts of first-degree sex trafficking and two counts of promoting prostitution. Police would not say whether the pimps have been charged.

The case is part of a pattern of trafficking of juveniles in the Twin Cities that has resulted in rising frustration with Backpage.com, which police and politicians say has become an out-of-control marketplace for prostitution. On Thursday, the Minneapolis City Council is scheduled to get an update on the city's efforts to stop sexual exploitation of minors, as well as consider a resolution to call on Village Voice Media to shut down the "adult services" section of Backpage.com.

Village Voice Media, Backpage.com's owner, says it has cooperated with investigators but has resisted the pressure to shut down.

Last month, two St. Paul men were charged with pimping two teenage girls at an Eagan hotel and threatening them with a gun after luring customers through a Backpage.com ad.

Minneapolis Police Sgt. Grant Snyder, who is investigating the case of the Eau Claire girls, said it's part of an initiative to identify and track high-risk runaways who are at risk of being exploited. He said the police are partnering with the federal Department of Homeland Security.

"We're continuing to look for and identify other possible victims," Snyder said.

According to the criminal complaint, the girls told police that they ran away together to Minneapolis. They met a man named "E," who persuaded them to become prostitutes, and he became their pimp, taking half the proceeds. For a time they worked out of motels and then were taken by another man to the house on Oliver Avenue N., where Warborg told police she lived.

Mahmood Khan, the landlord, said he didn't know that a woman was living there. He said he had been renting it to Robert Williams since February. The man recently stopped returning his calls and was behind on rent, so he was seeking to have him evicted, Khan said.

"I've been there a few times and didn't see anybody else," he said. He said he went to the residence about two weeks ago to fix a door and saw only the man.

Snyder said the house had been raided earlier this year, and its occupant, Robert Donelle Williams, was charged with aiding and abetting and aggravated robbery in the first degree after he arranged a robbery using a vulnerable adult as a prostitute. The complaint said Warborg told police that she accepted $100 for letting the girls and the pimp use her house, and that she gave methamphetamine to one of the girls and took out ads on Backpage.com.

Snyder said that the girls were in Minneapolis for two to three weeks, but they may have been exploited in other cities as well. He said the investigation moved quickly because the girls had been identified and the police knew they were being exploited.

Minneapolis police learned July 26 about the missing 15-year-old and that she might be involved in sex trafficking in the Twin Cities. The girl had called her family since running away, and police found that number associated with the Backpage.com ads showing the girls dressed in lingerie and offering intimate contact, the complaint said.

The GPS location on the cellphone led officers to the house on Oliver Avenue N.

masako.hirsch@startribune.com • 612-673-4263 pwalsh@startribune.com • 612-673-4482