Just an interesting assumption here. Todd Johnson was a dedicated follower of Red John. It was him who saved Jane in Season 2 Finale. (I believe Red John would use one of his followers well enough rather than show up in person and save Jane himself - he's smarter than that)

Todd Johnson spoke 'Tyger Tyger' in his last hours to let Jane know it was him who had saved Jane. After Todd Johnson was caught as the cop killer he knew he was going to serve indefinite jail time. He had to tell Jane about how he had saved him and try to make his sentence easier. 

O'Laughlin came to know this and burned him alive before Jane arrived or before Todd had revealed anything related to Red John.