The 53-year-old coach was full of praise for the former Genoa man and stated that the defender is an example to follow both on an off the pitch
Italian police searched the 25-year-old's room at the Azzurri's training base earlier on Monday, and the defender was subsequently removed from coach Cesare Prandelli's provisional Euro 2012 squad.
Criscito has already expressed his determination to clear his name, and Spalletti had nothing but praise for the player, whom he signed last summer.
"It is clear that the police are doing their work, but I know Criscito and he is a great player and a great man," he told Rai.
"There are no doubts about him, I would stick my neck out for him."
Meanwhile, Italian Football Federation (FIGC) president Giancarlo Abete also commented on this matter.
"To be honest, I am very sad about what happened with Criscito.
"It is fair that the boy is given the right to clear his name, but this is surely a bad day for the Italy national team."