City of London Police announced they arrested four suspects, two men, and two women, on accusations of running tech support scams.

Police say Microsoft played a big role in the investigation after "analyzing tens of thousands of [UK] Action Fraud reports and working with other affected organizations [...] to attempt to trace the source of the problem."

Tech support scams were operating out of India

Microsoft's and City of London Police's work have allowed investigators to track down the operators of several tech support scams operated out of call centers in India.

The arrests took place on Tuesday, June 27, 2017.  Sussex Police Cyber Crime Unit arrested a 29-year-old man and a 31-year-old woman in Woking, Surrey, while officers from North East Regional Special Operations Unit (NERSOU) arrested a 37-year-old man and 35-year-old woman in South Shields.

Investigators believe the losses from this operation are massive, estimated at "hundreds of millions of pounds."

Scammers posed as Microsoft, BT, TalkTalk employees

According to UK's Action Fraud center, the suspects were posing to be Microsoft employees in their conversations with victims. In other cases, the suspects posed as employees for two popular British ISPs, BT and TalkTalk.

It is unclear if suspects were cold-calling victims or using malicious software or websites to trick victims into believing they were infected with malware.

In recent months, we've also seen a rise in the number of email spam campaigns that used BT, TalkTalk, or the names of various other UK or US ISPs. These scam emails are telling customers they are infected with malware and have to reach out via telephone to a representative using an email provided inside the fake email.

One such campaign was spotted last month using BT's brand and offering protection against the WannaCry ransomware attacks.