(Reuters) - A former Los Angeles-area elementary school teacher was arrested on Wednesday on suspicion of sexually assaulting 20 children and one adult, police said.

Robert Pimental, 57, left his job teaching fourth grade at George De La Torre Jr. Elementary School in Wilmington when the investigation began in March, the Los Angeles Police Department said.

Pimental had been employed by the Los Angeles Unified School District since 1974. Bail was set at $12 million.

The arrest is the latest case of alleged abuse by an educator from the school district.

Last year, elementary school teacher Mark Berndt was accused of taking bondage-style photos of students, some with cockroaches on their faces.

Berndt, who taught at Miramonte Elementary School for more than 30 years, pleaded not guilty in February to 23 counts of lewd acts involving children.

(Reporting by Tim Gaynor; Editing by David Brunnstrom)