AURORA, Colo. — A 34-year-old Colorado middle school teacher is charged with sexually assaulting and exploiting students over the past four years.

Brian C. Vasquez was arrested last week at Prairie Middle School in Aurora and appeared in court Monday on 31 felony counts, including 11 counts of sex assault on a child by a person in a position of trust and 10 counts of sex exploitation of a child. Prosecutors said they had identified at least five victims.

Vasquez did not enter a plea Monday and he remains jailed with his bail set at $200,000. His next court hearing is set for Oct. 31.

Deputy Public Defender Elsa Archambault has been appointed to represent Vasquez. The public defender’s office does not comment on cases.

Vasquez had been a social studies teacher at Prairie for seven years. He is on administrative leave.