Susan was Noor Zahi Salman's teacher at her middle school in Crockett, California. ABC News is not using Susan's full name or showing her face at her request.
"Noor had difficulty with retention. She had difficulty with conceptualizing, understanding — all challenges to her," Susan said. "She tried hard. She was very sweet."
Her family confirmed that Susan was Salman's special education teacher and that she was enrolled in special education classes.
"Noor is completely innocent and [was] unaware of the attack," the statement said, adding that she doesn't understand "cause and effect." The family said Salman was enrolled in special education classes because she needed extra help in school.
Omar Mateen and Salman, now 30, were married in September 2011 after meeting online.
The FBI investigation is ongoing.