In a note, which was shared by a family friend on Facebook, the 13-year-old detailed how his treatment at Holy Angels Catholic Academy left him feeling utterly helpless.
'At first it was good. Lots of friends, good grades and a great life, but I moved and went back and it was different,' Daniel wrote.
'My old friends changed, they didn't talk to me, they didn't even like me.'
The 13-year-old then wrote about a fight he had with a student and former friend, which led to the other pupil being punished. His former friend blamed him for getting in trouble, something that only worsened the bullying.
'They continued, I gave up, the teachers either they didn't do anything! Not get them in trouble even though they did trouble, I got in trouble instead because [the student] was mad at me because he believed I failed him.
'I told all the teachers nothing except one… she was the nicest teacher ever she understood and did something but it didn't last long.
'I wanted to get out, I begged and I pleaded. Eventually I did, I failed but I didn't care. I was out that's all I wanted.'
Daniel wrote his letter on June 30, as he desperately wanted to make sure he would be able to start new at another school, Brooklyn's Xaverian High School, in the fall, the New York Daily News reports.
His shattered mother, Maureen Fitzpatrick, said his son was let down by the school.
'Danny said that he was afraid of his teachers. He felt like the whole school knew what was going on and was laughing behind his back. They humiliated him.'
'My son shouldn't have to die to be heard. There's something wrong with the adults in authority positions when kids can't go to them for help.
'No parent is supposed to bury their child.'