A man posing as an official Microsoft tech support worker has swindled victims out of $3 million over the course of four years through a scam campaign.

Court documents reveal that Bishap Mittal created a company called Capstone Technologies LLC along with an unnamed accomplice through which the pair bought Google and Bing adverts to promote the site in the respective search engines as well as appearances on adware popups from various global developers.

If a user were to land on the website or be greeted with the man's sponsored adware, they would be met with an official-looking message disguised as one from Microsoft, telling users to contact a customer support number.

The adware which the site sponsored would "temporarily lock users out of their computers and show an inflammatory and misleading representation of diagnostic systemic network infirmities such as viruses", read the court documents.

Once the number was called, users were directed to a call centre in New Dehli, India and on the end of the phone operators would remotely connect to a victim's computer and follow a script to convince users that their computer was having issues. From there, users were told that they needed to pay for unneeded tech support the price of which ranged between $200 - $2,400.