The inquest into the death of M16 spy Gareth Williams heard today that he was either dead or unconscious when he was discovered in a red North Face holdall in the bath of his flat in 2010.
Two video reconstructions showing experts trying to escape from identical sized bags were later displayed in court.
Second witness Peter Faulding, a former Parachute Regiment reservist who specialises in rescuing people from confined spaces, made 300 unsuccessful attempts to lock himself inside the 81cm x 48cm holdall.
He described theories that Mr Williams got inside the holdall by himself as "unbelievable scenarios" and said that a third party was present in the incident.
He went onto suggest it would have been "very easy" to fold the dead spy's arms and place him in the holdall as long as rigor mortis had not set in.
Earlier in the day, the inquest heard from former military expert in confined spaces, William Mackay. He was asked by the Metropolitan Police to reconstruct what might have happened to Williams and move into an identical bag, using a similar key, unaided and in a bath.
MacKay who is of a similar physical stature to Williams compiled a report including photographs and a DVD which were played in court. He managed to force his way into the bag, but struggled to pull the zip shut.
The reconstruction demonstrated that it was possible for the man to force the bag open from the outside when it was locked by using a pen and sliding the zip, but he was unable to close the bag from the inside.
Mackay, who had another person present with him for safety reasons, tried more than 100 times to close and lock the bag from the inside over the last year.
The reconstruction replicated Williams' situation in every respect except for the lack of oxygen and heat.
The inquest was adjourned until Monday.