LAKE ELSINORE - Twin sisters, both former teachers at Lakeside High in Lake Elsinore, have been charged in connection with a case of lewd acts with an underage girl who was a student at the school.

Charges were filed by prosecutors Tuesday against Franca and Antonia Munoz Juvera, 26, as well as 19-year-old Eileen Elizabeth Valerio, according to Riverside County Superior Court records.

The charges come exactly a year after the alleged crimes were committed, according to court records and nearly a year since the three were first arrested in the case.

"This was a lengthy, ongoing investigation," district attorney's office spokeswoman Ingrid Wyatt said Wednesday when asked why it took 10 months after their arrest to file criminal charges against the three.

The twins lived with Valerio in a Rancho Cucamonga apartment when they were first arrested in December. Some of the alleged illegal acts may have happened there, police have said.

Franca Munoz Juvera has been charged with two counts of lewd acts with a child while her sister and Valerio are charged with conspiracy to commit a felony, court records state.

Authorities have previously said that they believe Antonia Munoz and Valerio helped facilitate the sexual abuse of the underage girl by Franca and that neither reported the alleged crimes.

In an interview with The Californian in March, Lake Elsinore police detectives said the alleged victim in the case wasn't being very cooperative with their investigation "because she says she is in love with (Franca)."

Wyatt said there wasn't any sudden new evidence that led to the charges being filed after so long.

"The investigation just culminated into enough information to where we could file charges," she said.

The twins were both first-year teachers with the Lake Elsinore Unified School District when arrested in December. Franca taught math and Antonia taught chemistry, district officials said earlier this year.

On Wednesday, Superintendent Frank Passarella issued a written statement after learning charges had been filed.

"These two probationary teachers were not reflective of the high quality and dedicated educators within the Lake Elsinore Unified School District," the statement said, adding that they were placed on paid administrative leave right after they were arrested.

"As of June 2007, these two individuals were no longer employed by the district," according to the statement.

District officials declined any further comment, saying this was a personnel matter. No information about whether any of the three women have been arrested was available Wednesday night.

Court records state that arrest warrants have been issued for them and they are scheduled to be arraigned at the Hall of Justice in Riverside today.

- Contact staff writer John Hall at (951) 676-4315, Ext. 2628, or jhall@californian.com.