LAPD Capt. Fabian Lizzaraga told the newspaper Pimentel is suspected of inappropriately touching the children over and under their clothing.
The Police Department said the teacher's name was spelled "Pimental," but the school district and public records give the spelling as "Pimentel."
Police did not know if he had hired an attorney. A woman who picked up the phone at a number listed for Pimentel hung up when asked about a lawyer or comment from family.
There have been several high-profile recent cases of Los Angeles teachers accused of sexually abusing students. More than 225 parents and students are involved in various claims for damages against the district after Miramonte Elementary School teacher Mark Berndt was arrested a year ago and has pleaded not guilty to 23 counts of lewd conduct.
In December, a jury ordered the district to pay a boy molested by an elementary school teacher $6.9 million — among the largest awards in the history of the school system.
The jury found the district liable for the repeated molestation of the 10-year-old student in 2008 and 2009 by teacher Forrest Stobbe at Queen Anne Elementary School in the city's mid-Wilshire district.