Yoink!

They had no proof. He knew that they knew he had done it but they didn't have any proof. It was a huge distinction and it was the difference between him keeping his freedom or being locked away for decades. They continued to question him, probing him for information that they could use against him or find the proof they needed to put him away. He smiled and continued to block their every inquiry by feigning his innocence for a crime they all knew he committed.

It sounds like he's playing a dangerous game of cat and mouse with the authorities. Maintaining his innocence without proof could be his only defense strategy.