Investigators said Kennard kept the relationship well hidden.
"She took him in as part of the family," explained Irondequoit Police Investigator Sergeant Mark Bean. "He would spend nights at the house. He would do activities with the family. So, she tried to make him feel important."
Kennard, who is married, was hired as a teacher aide in the East Irondequoit Middle School in December, 2009.
Bean said the relationship with the boy began in 2010 when he was no older than 13.
"She felt that he had some family needs that weren't fulfilled by his family. It's a process that maybe she was looking for a victim or she generally became concerned and something happened. It evolved into a relationship that at this point we believe became sexual."
They say the sexual contact only took place at her house.
According to Bean, Kennard began acting strangely around her colleagues last week. They reported it to district officials Thursday morning, and by Friday she was arrested and charged with second degree rape and second degree criminal sex act. Both charges are felonies.
"Some of the employees were just concerned about her emotional connection to him," Bean added.
Kennard didn't answer the door when we stopped by, nor did she return any of our phone calls.
People we spoke with find the allegations disturbing.
"I think it's absolutely dysfunctional and sad to hear," said Aurelien Bouche-Pillon, who lives in Irondequoit.
"I'm appalled," added parent of seven, Diane Ford. "I work in a school district myself. Any professional, working with children, it's just gripping not only form a parent perspective but form a professional standpoint. "
Investigators said the boy's family had no idea what was going on. They added everyone, including the student, is cooperating.
"This is an ongoing investigation. We're out there to make sure that there are no second, third or fourth victims."
During her arraignment on Friday, the Irondequoit Town Justice issued an Order of Protection against Kennard, meaning she cannot have any contact with the now high school student.
The district has put her on administrative leave.
Police say her husband plans to stay by her side.