The Failed Attempt
The Worst Mistake of His Ending Life
The author created suspense by having unanswered questions, an obvious yet intriguing plot, and by incorporating the feeling of never going back.
"Seven years ago, he had committed a crime. It was a crime so terrible that even he could not believe that he had done it."
The author created the suspense by having the unanswered question of "What was the horrible crime that Boris felt ashamed of?
""To the next prisoner who find this paper," Boris read. "I escaped the horror of this cell by this passage. May you share my good luck."" ... "He read on, "This is the only way out!" The message was signed with two initials, "N.G.""
Of course the reader suspected that at the beginning of a mysterious tunnel a note that claimed freedom might be wrong because it's the beginning of the tunnel, but still it created suspense because as a reader you still don't know what is going to happen.
"Suddenly, the tunnel sloped down at a sharp angle. Boris's feet slipped forward. He landed on his back. He slid deeper and deeper into the tunnel." ... "He could never go back."
As soon as you incorporate the feeling of never going back in a story, the stress is on the story to work out the problem and solve it in the future. As of for the reader the suspense is on for everything to work out.
By having unanswered questions, an obvious yet intriguing plot, and by incorporating the feeling of never going back the author created suspense.