Three people have been arrested as part of an investigation into an alleged £3 million ($4m) bribery case relating to the construction of Microsoft data center in the Netherlands.

The UK’s Serious Fraud Office (SFO) announced on Wednesday that it had launched an investigation targeting UK company Blu-3 and former associates of the global construction firm Mace Group, and had raided five properties to look for evidence.

Individuals at Blu-3 are suspected of paying more than £3m ($4m) of bribes to former associates of Mace Group in relation to the construction of the data center.

More than 70 SFO staff searched four homes and one commercial property across London, Kent, Surrey, and Somerset on Wednesday, and three individuals were arrested for questioning.

A property in Monaco was also searched, with SFO officers assisting the principality’s authorities.

Blu-3 is a firm that helps manage construction projects, and according to its website has an ongoing association with Mace, having worked with the construction company on projects including The Shard in London.

It is also involved in data center projects around the world, and its website refers to “Project Nimble,” a €19.4 million ($22m) project to develop a hyperscale campus in Middenmeer, the Netherlands.

The data center involved in the case was not specifically named by the SFO, but Microsoft has a large campus under development in Middenmeer. Google also operates in the region.

Nick Ephgrave QPM, director of the Serious Fraud Office, said: “Paying bribes to do business undermines our financial markets, the reputation of British companies and the rule of law and will not be tolerated.

“Today’s action is a reminder that we will take rapid and robust action to tackle suspected bribery and corruption wherever it appears – at home and overseas.”

The UK’s solicitor general Lucy Rigby KC MP, added: “Bribery undermines the values of fairness and playing by the rules, and hurts individuals, businesses, and our wider economy.”

“This government is committed to tackling all forms of bribery to protect working people and ensure criminals are brought to justice.”