A 34-year-old high school teacher believed to be having a sexual relationship with a 17-year-old former student was arrested today in San Diego.

Kelly Watson was taken into custody at 10:55 a.m. on suspicion of sexually assaulting a 17-year-old boy she met when he was a student in her class at the New Haven residential school in Vista, said Lt. Anastasia Smith of the San Diego Police Department.