TAMPA — A year after former Tampa Day School principal James Larkin was sentenced to 10 years in prison for sexually abusing two teenage boys, the school is facing allegations of negligence from a student's mother.In a lawsuit filed late Tuesday in Hillsborough County's civil court, the mother of a Tampa Day School student who was molested in 2014 says the school's leaders failed to act on multiple warning signs indicating that Larkin's relationship with her then-14 year old son was not normal. The lawsuit claims that Larkin's favoritism toward the teenager was "open and obvious" to Tampa Day School teachers and head of school Lois Delaney.Larkin, 65, who pleaded guilty last April to sexually abusing the 14-year-old Tampa Day School student as well as another teenager, is also named in the suit.SENT TO PRISON: Once a beloved educator, James Larkin sentenced to 10 years for sexual abuseThe school, which specializes in teaching children with mild to moderate learning disabilities, fired Larkin shortly after the 14-year-old's allegations surfaced. Reached by phone on Wednesday, Delaney declined to comment, as she had not yet seen the lawsuit. An attorney for Larkin, who is serving his sentence at a prison in Doral, also declined to speak on his client's behalf.The complaint describes how Larkin went about befriending the teenager, who had attention deficit disorder and struggled in school. Because the boy's father had died in 2009, Larkin stepped in as a surrogate, showering the student with attention and affection.According to the complaint, Larkin texted the student — known only by his initials R.R. in court documents — after school hours, he invited the student to each lunch with him alone, and he would sometimes enter the boy's classroom to whisper in his ear, or excuse him from the lesson. At one point, Larkin created a "Dad's club" at the school, and chose himself to serve as R.R.'s stand-in father."Larkin bragged to R.R. that he liked the headmaster, Mrs. Delaney, because she gave Larkin latitude to have a private relationship with R.R. and did not ask many questions," the complaint states.In March of 2014, Larkin offered to babysit the student for a weekend while his mother was out of town. One night, he entered the boy's bedroom and fondled him as he lay in bed. According to the complaint, Larkin also molested the boy on several occasions in school, while the student was alone in his office.Before he was charged with sexually abusing two boys, Larkin was known as a beloved private school teacher. From 1978 to 2009, he was headmaster at St. John Greek Orthodox Day School in South Tampa. One of the teenagers in the criminal case was a student there in the 1980s when Larkin sexually abused him, an event the former student brought to prosecutors' attention after allegations arose at Tampa Day School.Adam Horowitz, an attorney representing the Tampa Day School student and his mother, said he is aware of at least one other St. John student who says he was molested by Larkin. But in that case, Horowitz said, the statute of limitations has run out.The lawsuit does not specify how much money Horowitz is seeking on behalf of the student and his mother."We'll decide what we ask for when all the evidence is gathered," he said. "There's no amount of money that can undo the harm that occurred."