A 34-year-old Farmington woman is facing charges after police say she sexually assaulted her friend’s 13-year-old son. Farmington police arrested Mandy Lynn Thibodeau at her home Wednesday on a charge of gross sexual assault. Police said they learned of the alleged assaults from the boy’s mother. Police said the allegations stem from incidents that occurred last month. Thibodeau is being held on $1,560 cash bail at the Franklin County Jail.