SAN DIEGO -- A fifth-grade teacher accused of having sex with two of her former students -- including one of whom was 12 -- pleaded not guilty Wednesday to multiple child molestation charges, including statutory rape.

Trial for Adrienne Feistel, who is free on $50,000 bail, is scheduled for Sept. 3.

Deputy District Attorney Wendy Patrick Mazzarella said outside court that Feistel had sexual relations with a former student beginning when he was 12 and had sexual intercourse with another former student starting when he was 16.

Feistel, 35, kept in close contact with the alleged victims and their families once they left her class but the boys didn't know each other, the prosecutor said.

The younger boy, now 15, testified during a two-day preliminary hearing last month that the sexual activity with Feistel began about two months into his seventh-grade year.

At some point during that year, Feistel moved in with the boy's family because she was having marital problems, he testified.

The teen -- who will be a high school sophomore next year -- said Feistel snuck into his bed and had sex with him a couple of months after moving in.

He said he ended up telling authorities what happened last August when police were called to his home to investigate a confrontation between his mother and sister.

"I decided to stop and not do it anymore," the boy testified. "She tried to kiss me and I wouldn't."

Investigators allege Feistel pressured the boy into sex acts between August 2006 and last year.

Another young man testified that he had sex with Feistel, but he claimed it didn't happen until he was 18.

District attorney's Investigator Barbara Rudestill testified that the second alleged victim told her and another investigator that he had sex with Feistel two to three times in San Diego.

A fellow teacher said she accompanied Feistel to see a counselor and the defendant ended curled up in a ball on the floor saying, "What if I did something to a student?" Rudestill testified.

That teacher said Feistel was obsessed with Mary Kay Letourneau, a former elementary school teacher convicted of raping a 12-year-old student, whom she eventually married, Rudestill testified.

Another teacher told the investigators that Feistel had a "favorite student" every year, and it was usually a boy, Rudestill testified.

Authorities allege the sexual relations between Feistel and the older boy began in 2004, when the older alleged victim would have been around 16.

Feistel taught at Rosa Parks Elementary School but went on leave Feb. 27, 2006. She resigned from the district on Sept. 1 of that year.

Feistel's attorney, Anna Yum, told the judge that the alleged sexual relationship with the young boy never happened.

The attorney said the credibility of witnesses, especially some of the younger witnesses, will be important if the case goes to trial.

After the preliminary hearing, Judge Gale Kaneshiro ordered Feistel to have no contact with any minor children, including her 6-year-old son, unless accompanied by an adult who knows about the charges against the defendant.

Each charge of committing a lewd act on the younger boy carries a maximum of eight years in state prison upon conviction, the prosecutor said.