The document says Singapore Officials told ONA they made this assessment on the basis of “technical intelligence”, which is likely to relate to intercepted communications.....
Actually Mahathir could have told MM Lee that he has all the evidence - except people just refused to believe him at that time because they were disillusioned with the doctor. He cried wolf too many times I think. It's incredible, unbelieveable, but true of a DPM! Mahathir has said it before, but need to respect the judiciary in order not to be in contempt.
In Boleh-land, anything is boleh!