A Florida teenager accused of bludgeoning his parents with a hammer believes he has "such a strong defense" he'll reach a plea deal to avoid a life sentence.

But for now, 18-year-old Tyler Hadley has pleaded not guilty in the deaths last July of Blake and Mary-Jo Hadley. Police say Hadley threw a huge party at his parents' house after their deaths. 

In jailhouse letters to friends and family, he expresses hope he can avoid a life prison sentence or be placed in a state hospital. 

The teen repeatedly complains of depression in his letters, and says he cries daily and prays for forgiveness. 

The letters are part of a batch of documents made public by prosecutors.