First Minister Nicola Sturgeon is under renewed pressure to explain why a Covid-19 outbreak at an Edinburgh hotel in February wasn't publicly revealed until this week.
Ian Murray, the Labour MP for Edinburgh South, wrote to Sturgeon asking for details about a conference held by Nike in the capital.
The event was attended by delegates from around the world - at least 25 of whom were later confirmed to have been infected by coronavirus, including eight resident in Scotland.
Health officials were aware of the outbreak by March 2 but did not reveal the information publicly.
The Edinburgh outbreak took place several weeks before lockdown was implemented and was only revealed on Monday by a BBC Disclosure documentary.
Speaking at her daily media briefing on Tuesday, Sturgeon said "all appropriate steps were taken" to protect public health during the weeks leading up to lockdown.
She added patient confidentiality meant small numbers of cases could not be publicly identified at that time - but they were included in the regular NHS reporting system.
"On the Nike event, I was satisfied then, and was satisfied now, that all appropriate steps were taken," she said.
But Labour's sole Scottish MP said today that explanation didn't go far enough.
"You said that you are satisfied that all necessary steps were taken," Murray said in his letter.
"I don’t doubt this to be the case, but how many of the conference attendees were in touch with the wider public?
"How many used local transport, shops, restaurants, bars, taxis, the airport, trains, and other local services?
"Unfortunately, I believe your initial response to some of these questions at your daily press conference failed to provide the clear answers that people deserve.
"Firstly, you dismissed concerns about these revelations as being ‘politicised’. It is more important than ever that government decisions during a health pandemic are scrutinised and that ministers are held to account.
"That is not ‘politicising’ an issue – it is a vital aspect of our democracy."
Murray's letter continued: "There are many reasons why there is public concern about this cover-up. At the time of this outbreak in February, we were still several weeks away from lockdown.
"It is now apparent that your government was too slow to enter lockdown, but had this information been made public at the time then we may have been able to enter lockdown earlier and save more lives.
"Not only would this have made any restrictions more justifiable to the public, it would have allowed independent expert scientists and researchers to make their own recommendations."
A Scottish Government spokesman said: “As the First Minister has said, all appropriate steps were taken to ensure public health was protected.
“The group at increased risk of COVID-19 were all identified and all contacts were traced, so public health authorities were satisfied that there was no further infection risk.
"NHS Lothian and Edinburgh City Council also worked closely with the conference venue to provide advice for close contacts of delegates and infection prevention and control considerations.
“All of the cases linked to this event were traced by their close contact with this case, or contact with conference delegates who tested positive after the event.
"Therefore it is not an example of community transmission, which would require a confirmed case, with no known history of international travel to a risk area, or link to close contact of such a case."
