(AP) — A delay in reporting as missing a British spy whose naked and decomposing body was later found locked inside a sports bag frustrated police inquiries into his mysterious death, witnesses told an inquest hearing Thursday.

Gareth Williams, 31, worked for Britain’s secret eavesdropping service GCHQ but was attached to the country’s MI6 overseas spy agency when his remains were found in August 2010 inside the bag and in a bathtub at his central London apartment.

The inquest hearing was previously told the spy’s manager at MI6, formally known as the Secret Intelligence Service, didn’t raise the alarm for a week after Williams first failed to appear for work, complicating the task for investigators.

Members of Williams’ family walked out of the hearing in tears Thursday as a second colleague- an intelligence officer identified only as SIS F – acknowledged that the delay “had some impact on the police investigation.”

“We are profoundly sorry about what happened,” she told the hearing, speaking from behind a screen to preserve her anonymity. “It shouldn’t have happened and we recognize that the delay in finding Gareth’s body has made it even harder for the family to come to terms with his dreadful death and we are truly sorry for that.”

“I also appreciate the delay had some impact on the police investigation,” the intelligence officer said.

Forensic expert Denise Stanworth said the delay had meant that toxicology tests conducted on the spy’s body couldn’t be totally reliable in determining whether Williams had been poisoned before his death.

“In terms of many of the drugs, reliable, but in terms of the more volatile substances, not that reliable,” Stanworth told the hearing.

Anthony O’Toole, lawyer for the Williams family, told the hearing that relatives believed MI6 colleagues had shown a “total disregard for Gareth’s whereabouts and safety,” after failing to alert senior managers and relatives about his disappearance for a week.

He said that relatives also believe police likely lost vital chances to solve the case. So far, detectives have made no arrests and are still not certain exactly how Williams died.

“Because of the decomposition of the body, any forensic evidence that could have been derived from it has disappeared, so the police investigation has in essence been almost defeated,” O’Toole said.

Coroner Fiona Wilcox’s inquest hearing must attempt to determine when and how Williams died, and if anyone else could have been involved.

The spy’s colleague SIS F told the hearing that an internal review had concluded that Williams’ death was not connected to his work, which had included operational assignments with MI6.

MI6 had uncovered “no evidence of any specific threat to Gareth and we concluded that there was no reason to think his death was anything to do with his work,” the woman told the hearing.

She also rejected suggestions that the spy’s lifestyle could have made him vulnerable.

Police found thousands of pounds (dollars) worth of luxury women’s clothing and shoes in his apartment and discovered that he had visited bondage and sadomasochism websites, including some related to claustrophilia – a desire for confinement in enclosed spaces.

Other witnesses have told the hearing that Williams was not a cross-dresser, but often purchased expensive clothes to give as gifts to female friends.

Williams’ colleague said MI6 had not found any cause for alarm in the spy’s background when he was vetted for his position. “There’s no set template as to what (an employee’s) lifestyle should be. Individuals have lifestyles and sexual choices which are perfectly legitimate,” she told the hearing.