The premises will be searched and it is possible that the person under investigation could bearrested and taken for interview under caution bythepolice.
Ten supposed middlemen in Latvia were arrested last year, and suspects said to be responsible for writing and deploying the code were picked up by Russian police in July.
The three men were arrested under the Fraud Act and are being detained at a police station, where they will be questioned bypolice and FSA investigators, according to the agency.
Another gay man from Newcastle, who was fined more than two decades ago for gross indecency at the age of 20, said he was recently told by Northumbria Police that he would bearrested if he refused to provide a DNA sample.
He has been warned he will bearrested when he leaves the embassy for breaking the terms of his bail conditions, necessitating the 24-hour guard by Metropolitan Police officers.