Ive bern(stein) over this a few times. Tariq Panja is the NYTT journalist breaking these "stories". Panja started his journalist career at the Manchester Evening News, where he developed David Gill as a source I believe. Leaks are coming from a senior figure at UEFA and Leterme is quite insistent that they aren't coming from him or any other member of the CFCB. David Gill is not part of the CFCB so Leterme is technically correct that, if Gill is the one providing Panjs with information, the leaks aren't coming from that source.
Inadvertently therefore, by telling the truth, Leterme has made it quite clear who the potential source is.