The MI6 cipher officer found dead in his flat in a padlocked bag had previously been rescued after tying himself to his bedstead, an inquest was told, as police said there was nothing to link his death to his intelligence services work.

Gareth Williams's decomposed body was found in the bag in the bath at his home in Pimlico on 23 August 2010, and 21 months later police remain baffled over the circumstances of his death.

But his former landlady, Jennifer Elliot, told the inquest that three years before his death, she and her husband had heard Williams call for help at 1.30am from the annex flat he was renting from them in Cheltenham, where he worked at GCHQ.

They let themselves in with the spare key and found the codes expert lying on his back on the bed, in boxer shorts, with his hands tied to the bed posts with material so tight it had cut his wrists.

In a statement read to the inquest, Elliot said she and her husband had both been in shock. Her husband asked Williams: "What the bloody hell are you doing?" Williams told them: "I just wanted to see if could get myself free."

The statement added that he did not appear sexually aroused, and was "very embarrassed, panicky and apologetic."

The couple, who never spoke to anyone about the incident, said they concluded it was "sexual rather than escapology".

The Westminster coroner, Fiona Wilcox, heard that Williams was only reported missing seven days after he failed to turn up for work, despite missing two meetings, and working in a small office of four people, two of whom were away.

He had been on secondment from GCHQ to MI6. His line manager, known only as Witness G, said that at first he believed Williams's absence was "a misunderstanding" and it was possible "he was engaged in other activities that I was unaware of". G said he had made attempts to contact Williams by telephone on day two of the unexplained absence. G was away from the office the following two days, but on Friday 20 August (day 5) he made more attempts to make contact through phones and email, then visited William's flat. He got no response on the intercom.

Only after the weekend did Witness G finally report him missing and contact William's sister, Ceri Subbe.

The coroner said she was struggling to understand why no action was taken sooner, and G was asked to explain the delay by the family's lawyer, Anthony O'Toole. "What concerns the family is that Gareth was in a profession in which there are risks. And they are concerned that such a long time took place, and four days were effectively left without any investigation."

G told the inquest "with hindsight I wish I had taken different steps over that week". He added there was nothing to indicate Williams was at risk at that time.

Evidence from Carol Kirton, an assistant at the upmarket west London fashion store Dover Street Market, stated testified that Williams regularly bought women's clothes.

In a statement, Kirton said he was shy and "on a mission to buy" and told her the clothing was for his girlfriend, who was "tall and slim". Police found £20,000 worth of designer women's clothing at his flat and 26 pairs of shoes and boots, many in pristine condition, still in tissue paper.

His friend Elizabeth Guthrie said Williams, who often used another name and had several phones, might have bought the clothing "as a support strategy" for somebody. "Certainly they would not have been for him," she said. Asked about his sexuality, she said: "I have a personal view that he was straight."

Questions were raised about the police investigation as A senior SO15 counter-terrorism officer, Supt Michael Broster, the conduit between homicide and the intelligence agencies, said there was "no link as far as we can tell, between his work and his death".

Williams's personal laptop was examined, and there was nothing work-related on it. The inquest heard that he had visited Claustrophillia, bondage and sado masochism websites, O'Toole asked if Broster could guarantee evidence was not tampered with during the several days before police retrieved William's electronic equipment from SIS (Security Intelligence Services) and GCHQ.

He said he had been assured it had not. "So, its almost an Old Boys act. They told you that and you accepted?" said O'Toole. "Certainly not, said Broster. They're a responsible organisation." The hearing was also told no formal signed statement were submitted by intelligence witnesses questioned. Instead police compiled "notes" after interviewing, which witnesses did not see and which, according to O'Toole, contained "inaccuracies".

The hearing continues.