SEATTLE -- A man coerced a 12-year-old girl into prostitution, dictating how much to charge for sex acts until he was caught after the girl's family learned what was happening, police said.

The family filed a missing person report Jan. 9 after the girl failed to return home. They located her Sunday, four days later, after a woman who said she was the man's fiancee learned what was going on and called the girl's sister, police said. The family plans to obtain counseling for her, officers added.

"She is doing remarkably well, for all things considered," police Sgt. Ryan M. Long said. "I had a rather personal conversation with her for a while, and I was impressed with her resilience and her resolve."

Steven Lorenzo J. Leonard, 23, a transient who apparently befriended the girl was booked into the King County Jail early Thursday for investigation of child rape and promoting prostitution.

Leonard has an extensive record, according to documents obtained by KIRO 7 Eyewitness News. He has been convicted of escape, possessing stolen property, theft, obstructing a public officer and animal cruelty.

"She was approached by a predator," Detective Bryan T. Van Brunt said.

"You wouldn't think she was even an 18-year-old. It was abundantly clear she was a juvenile," Long said.

Police wrote that Leonard told officers the two had consensual sex, but that would still be a crime because the age of consent in Washington state is 16. Detectives said acquaintances also alleged that Leonard had befriended other young girls, raped them and coerced them into prostitution.

Vice detectives said the 12-year-old was the youngest they have encountered in a prostitution case in recent years.

"I'm disgusted. I'm overwhelmed with concern," Long said. "What I'm afraid of is what ones aren't we discovering?"

The girl told police that a mutual friend introduced her to Leonard on Jan. 9 and he invited her to hang out, then had unprotected sex with her that night and several times in the ensuing days. The two stayed at the homes of several women who described themselves as his fiancees, Long said.

Meanwhile, the frantic family called police daily.

"They were ready to start calling everybody, including congressmen," Long said. "They were reaching out, trying to get answers, trying to get people to start looking."

One evening, at Leonard's direction, the girl walked the street in south King County seeking "johns" as a prostitute and was paid by one, turning the money over to the man as he demanded, according to investigators.

Over the weekend a self-described fiancee became angry about the situation, dialed a telephone number she found in a school binder the girl had left at her house, and reached the girl's sister, telling her how to find Leonard and the girl in downtown Seattle, police said.

When relatives located the two in the downtown area Sunday night, "they just ran up and took her," Long said. "He was a little argumentative at first, but the relative who did the finding is a big guy."

After taking the girl to Harborview Medical Center for a rape examination, the family went to the police West Precinct and filed a report. The girl was interviewed Wednesday by Long and Brunt, who found Leonard that night on a street in West Seattle.

"It was pure happenstance," Long said. "We were looking for locations we thought we might find him in the future."