Police have launched an investigation after more than 300 people were discovered at a house party in Midlothian.
Officers were called to The Mansion House of Kirkhill in Gorebridge at 00:20 on Sunday.
They said the party was being run as a commercial event at the property, which rents for about £1,600 a night on Airbnb.
It was dispersed and a 29-year-old man was issued with a fixed penalty.
Organisers have been criticised for showing a “blatant disregard” for laws to limit the spread of coronavirus.
First Minister Nicola Sturgeon described the incident as “utterly irresponsible” and urged people not to attend house parties.
In a statement published on Facebook, the owners of the property said the man who made the booking for the entire weekend “seemed very pleasant”.
“We were then sadly as owners contacted at 1.30am Sunday morning by our old neighbours to say there was a huge rave and police were in attendance,” it added.
“We are seeking legal action against the organisers of this event and are devastated as a family that our trust was broken.”
The statement added: “It’s after all our family home and we did not feel safe being there after so many people had been.”
Police are now investigating culpable and reckless conduct charges against the people behind the party.
Indoor gatherings are limited to no more than eight people from three households and police can issue £60 fines at gatherings of more than 15 people.
Repeat offenders can be fined up to a maximum of £960.
Deputy Chief Constable Malcolm Graham, said: “Those attending this organised event showed a blatant disregard for the regulations in place to help save lives and prevent the spread of coronavirus.
“Anyone attempting to hold such an event, or any party in clear breach of the law, should be aware they will be met with a robust response from Police Scotland.”
The 12-bedroom Mansion House of Kirkhill can be hired out for a minimum of two nights and can sleep up to 34 guests, according to its AirBnB page.
However it says it cannot currently operate at maximum capacity due to social distancing rules.
Councillor Stephen Curran, chairman of Midlothian Police, Fire and Rescue Board, said: “Those 300 or so people didn’t just put themselves at risk of contracting coronavirus, they put residents across Midlothian and beyond at risk.
“We realise it can be challenging following the guidance but if the majority of us can do it then so can they.”
The Midlothian party was one of about 300 reported to police across the country last weekend.
Officers issued six fixed penalties.
Five were issued after officers attended reports of a house party in Kirkintilloch, East Dunbartonshire, at about 20:00 on Saturday, August 30, 2020.
Two men were also arrested in connection with a fight at the property.
Alison McCallum, director of public health at NHS Lothian said: “We must continue to help prevent the spread of coronavirus which is why it is critical we don’t socialise in the same way we did in pre-Covid times.
“That means we must meet with no more than eight people from a maximum of three households at a time indoors and no more than 15 people from a maximum of five households at a time outdoors.
“This is also why nightclubs are currently closed and larger gatherings such as house parties are not permitted.”