Alleged sexual abuse by ex-teacher 'horrific,' teachers union says The teachers union in the L.A. Unified School District spoke out on the arrest of a former elementary school instructor accused of sexually abusing 20 children and an adult, calling the alleged acts "horrific." United Teachers Los Angeles issued a statement saying union officials were "not familiar with details of the case" and that the accused ex-teacher -- identified by authorities as Robert Pimentel, 57, who taught at George De La Torre Jr. Elementary School in Wilmington -- was no longer a member of the union. The union will not be involved in his defense, the statement said. The allegations described are horrific. As teachers we have a duty to uphold the trust our students and their parents place in us," the union said. We urge our members and the community to cooperate with ongoing law enforcement investigations in this case. Pimentel was arrested Wednesday by Los Angeles Police Department detectives who had launched an investigation in March after several fourth-grade girls said they had been inappropriately touched, authorities said. The charges involve sexual abuse and lewd acts on a child and cover a period from September 2011 to March 2012, according to court records. Los Angeles police detectives suspect that Pimentel victimized an additional eight children and the adult, LAPD Capt. Fabian Lizarraga told The Times. He said Pimentel is suspected of inappropriately touching the children under and over their clothing. In January, a teacher at Miramonte Elementary School in the Florence-Firestone neighborhood was arrested for allegedly spoon-feeding semen to students in a classroom and taking dozens of photos of students. On Wednesday evening, L.A. Unified Supt. John Deasy said Pimentel and the school's principal were immediately removed when the district found out about the allegations in March. Deasy said he removed the principal because he was "dissatisfied" with how the incident was handled at the school. District officials prepared a "notice of termination" for Pimentel and the principal that they had planned to present to the Board of Education in April, Deasy said. But the two employees retired before the board meeting. He said Pimentel and the principal will receive their full pensions because they retired before any actions were taken. Richard Winton, Robert J. Lopez, Howard Blume and Kate Mather