NIST

As soon as Klaus saw who the sender of the letter was, he tried to close the door to his room as fast as he could.

Jayaa, who had delivered the envelope and was standing outside, was confused and put his foot on the door to stop him from closing it. "Hey, is everything okay?" 

"Yeah, I just need a second to read this here by myself. I'll be right down to talk to you."

Obviously, those words were not enough to make someone with a naturally curious spirit like Jayaa go away so easily.

"Hummm... Is it a letter from a girlfriend from jail or something?" Jayaa asked. He didn't understand that Klaus didn't want to share more details about the contents of the envelope