A 13-year-old Santa Rosa girl testified Monday she had phone sex with an East Bay man for a three-month period this summer before he drove to Sonoma County and attempted to help her run away from home.

Arnold M. Luz, 45, of Alameda was arrested Aug. 10 after being contacted by officers in the parking lot of Cook Middle School. The girl testified he was planning to bring her to his cousin's house so she could escape a troubled home life.

"I talked to him mostly every day when my mom didn't take away my phone," testified the girl in a barely audible voice, her dark bangs covering her eyes.

Luz, who remains in custody, stared across the courtroom from the defense table. He faces up to 22 years in prison if convicted.

The girl was the second witness in the two-hour preliminary hearing to decide if there is evidence for the charges.

She testified she met Luz in late April or early May on a telephone "party line" in which users create profiles and leave messages for each other. She said she used a fake name and described herself as being 16, although conflicting evidence suggests she claimed to be 18.

However, within a week of first contacting Luz, she told him she was really 13, she said.

"He liked that I was younger," she testified.

Right away, she said, she gave Luz her cellphone number and the two talked "three times a day," often about sex. They pretended she was a nurse or Catholic school girl, she said.

Their talks continued through most of the summer, she said. The last time they had phone sex was Aug. 10, a few hours before she called him back, crying, saying her mother was going to punish her for talking to a boy.

She asked him to meet her at Food Maxx on Stony Point Road but changed the location to the parking lot of Cook Middle School, which was closed for summer vacation.

Luz, who is unemployed and lives at home with his parents, hopped in his car and drove out, she said. He got lost on the way so the girl asked a woman to give him directions using her cellphone, she testified.

The woman became suspicious and called police, who arrived to find Luz talking to the girl in his car, Officer Jennifer James testified.

"I asked for his ID and he was from Alameda," the officer said. "Something seemed really wrong."

Luz agreed to come to the police station for questioning and later admitted having phone sex with the girl 10-15 times, Detective Stephen Bussell testified.

Also, Luz admitted knowing the girl was really 13, Bussell said.

He told officers he wanted a younger girl to "impress his friends," Bussell said.

Luz's attorney, Kristine Burk, questioned whether he knew her true age. She suggested the role-playing may have extended to her age.

Also, Burk argued Luz couldn't be charged with child molestation because he had no physical contact with her. Prosecutor Rosanne Darling countered he broke the law by instructing a minor to touch her genitals.

Judge Julie Conger agreed with Darling, finding Luz could be tried as charged on a count of continued sexual contact with a child under 14 and three counts of child molestation.