Jan. 24, 2013— -- A former grade school teacher in the Los Angeles Unified School District has been charged with sexually abusing 20 students, allegations that follow closely on the heels of two other LAUSD teachers charged with molestation in 2012.
Robert Pimentel, 57, who taught fourth grade in the district for 40 years, is accused of molesting children during two time periods, one child from 2002 to 2004, and 14 from September 2011 to March 2012. The investigation is ongoing.
The charges against Pimentel include eight counts of "substantial sexual conduct" and seven counts of "lewd and lascivious acts" on children under 14 years of age, according to court documents. All of the charges are felonies.
Police told ABC News affiliate KABC they expect more misdemeanor charges to be filed.
Police did not release any other details about the type of alleged abuse or the other alleged victims.
Allegations of abuse by Pimentel were first reported to the George De La Torre elementary school in March 2012, when several girls told their parents that Pimentel had inappropriately touched them at school, according to the Los Angeles police department.
Pimentel was immediately removed from his classroom and parents were notified, the district said in a statement.
"When the District first learned of the allegations, the teacher was immediately removed from campus, parents were informed, and the California Commission on Teacher Credentialing was advised," the statement said. "Dismisal proceedings were initiated. Before the Board of Education could act on dismissal, he chose to retire."
Two teachers at Miramonte Elementary School, also within the Los Angeles school district, had been charged the prior month with molesting children, sparking outrage from parents at the failure of district leadership to protect students.
Police said it took from March until this week to build a case against Pimentel.
"Due to the number of victims involved in this case, that's what took so long for it to culminate," Det. Gus Villanueva of the Los Angeles Police Department told KABC.
Pimentel was also accused of sexual abuse of one adult, though police did not release any details on that allegation. He will face arraignment today or Friday, according to the District Attorney's office.
The principal at Pimentel's school was also removed for his handling of the situation, KABC reported.
The district has been in upheaval over its handling of sex abuse allegations against teacher Mark Berndt, who allegedly spoon-fed semen to children and took their pictures. He is charged with 23 counts of lewd conduct and has pleaded not guilty.
The same month, teacher Martin Springer was arrested and charged with fondling girls in his classroom. He also pleaded not guilty.
Both men are awaiting trial, according to the Los Angeles Sheriff's Department.