A woman has been arrested as part of the investigation.
Raids were carried out at 11 addresses across the country on Wednesday and Thursday last week as part of an investigation into two linked cyber-attacks.
Police say those who have been safeguarded were discovered at three addresses that were searched in Romford and Ilford.
They are all from eastern Europe, with many coming from Romania.
The cyber-attacks were carried out in September 2018, and targeted a business in Basildon and a school in Chelmsford.
In both cases, malware was used to steal large amounts on money.
The school lost almost £62,000, while the business had approximately £162,500 stolen from its accounts.
A 25-year-old woman from Ilford was arrested on suspicion of money laundering. She has been bailed until June.
Detective Inspector Ian Collins, of the Kent and Essex Cyber Crime Unit, said: “We’ve worked very closely with neighbouring and regional forces to execute these warrants and further our investigations into these cyber-attacks.
“This is an incredibly complex investigation and we will continue to seek out individuals who we believe may have benefited from the proceeds of crime, or exploited others in order to do so.”
Raids were also carried out at locations in West Drayton, Croydon, Wisbech, and Epsom.
Computers, phones, cash and banking documents were seized from 10 properties, under the Proceeds of Crime Act.
Tags: Essex, Romford, Ilford