MERCED, Calif. -- A California high school teacher has been arrested, accused of molesting students on school grounds.

Jesus Rivera, a drama and Spanish teacher at Golden Valley High School in Merced, appeared in court this week, according to Sacramento, Calif., television statin KCRA. He is charged with sexually assaulting four students. Rivera pleaded not guilty.

Rivera also faces misdemeanor charges on suspicion of annoying or molesting children in incidents dating back to 2002.

"Jan. 12, a student came in to see me right after lunch time and shared with me some concerns that he was feeling about, some things that had happened between him and a teacher," Golden Valley High School principal Ralf Swenson said.

All of the alleged victims were teenage boys between the ages of 14 and 17 at time of the suspected incidents, according to Merced Police Detective Rod Dash, who is investigating the case. At least three of the alleged victims said they were molested on campus. And a fourth alleged victim said a molestation took place at Rivera's home.

Investigators said there is evidence that strange behavior took place at the drama building after hours.

"One of the more bizarre incidents that took place was he actually sucked on the toes of a student on campus," said Merced Police Department spokesman Rod Dash.

Rivera's attorney said the allegations are completely false, and that his client may be targeted because he is an openly gay teacher.

Swenson said he would send a letter to parents that explains the situation.

Rivera's bail has been set at $250,000.