MI6 spy Gareth Williams would have suffocated within three minutes after getting inside his sports holdall, an inquest heard today.
Poisoning and asphyxiation are the "foremost contenders" in solving the death riddle, pathologists said.
It also emerged scientists found traces of "at least" two unknown people in his apartment despite evidence Mr Williams rarely invited people over.
Forensic expert Ros Hammond said there were hopes of a breakthrough "within a matter of weeks" from DNA tests found on a green towel in his kitchen.
"There's hope," she told Westminster Coroner's Court. "The tests are still in progress and there may be some promising results from those tests."
Ms Hammond said a third party would not necessarily have left any DNA on his red North Face bag and padlock.
Whatever the coroner's verdict today at the inquest into the death of MI6 spy Gareth Williams, many questions will remain unanswered.
Last day of the inquest into the death of Gareth Williams
Experts can't rule out the possibility that the MI6 spy found dead in a bag, locked himself in unaided, before dying.