The texts were written by Xavier Dupont de Ligonnes, who is thought to have shot his family in the south of France in April 2011 and is still on the run.
"I think I’ve got a superiority complex, you could call it that. But it’s based on a simple observation: I belong to a group of people who are intelligent, determined, balanced and in good moral and physical health," writes Xavier Dupont de Ligonnes, French daily Le Parisien reports.
"Such people are rare compared to the masses," he writes.
The files offer insight in the thoughts of Dupont de Ligonnes, who is accused of killing his wife and four children. Last year, his family were found buried under the terrace of their house in the eastern town of Nantes. They had been shot and the main suspect Dupont de Ligonnes had disappeared.
The writings recovered on an Internet server show Dupont de Ligonnes was very religious, but also inconsistent.
"All my adolescence was devoted to religion and faith, under the influence of my grand-mother and mother. To such an extent that I did not rebel like other adolescents, nor indulge in drugs or run after girls," he writes.
But in other passages, he says he indulged in shop-lifting, had girlfriends, drank and smoked.
Dupont de Ligonnes also writes that he was intensely disappointed when he found out that his wife could be in love with other men.
"To realise after 15 years of marriage that she had physical desires for other men (...), was the greatest disappointment." he writes, "but again I am happier now that I must act to maintain the love of my wife."
Wife Agnes 49, daughter Anne, 16, and three sons were apparently shot several times in the head while asleep, around April 3 or 4.
Dupont de Ligonnes was last seen on April 15 when he left a budget hotel at Roquebrune-sur-Argens in the Var region on France's Mediterranean coast, abandoning one of the family cars in the car park.