Stephen Gallagher, 54, was taken into custody on Feb. 5.
Suisun City police say they had been investigating the allegations, said to have occurred between May 2016 and March 2017. During this time, Gallagher was a teacher at Suisun Elementary School and the alleged victim was a third grader in his care.
Police seek anyone else who believe they or someone they know may have also been victims.
Anyone with information is asked to contact Detective Jeremy Snyder at 421-7373 or email@example.com.