Fraud investigators have raided three homes as part of a major inquiry into a failed property company that owned several landmark buildings and owed investors millions. The Serious Fraud Office (SFO) made four arrests after dawn raids on Wednesday in Merseyside and Greater Manchester in relation to its investigation into Signature Group, which collapsed in 2020 owing up to £140m. The Liverpool-based company, which was founded by Lawrence Kenwright, spent seven years buying historic buildings in UK cities to be redeveloped into hotels, office spaces and high-end flats. These included Millennium House in Liverpool, Belfast’s Scottish Mutual Building and the Coal Exchange in Cardiff. It also owned a cruise liner that was marketed as a “flotel” and moored in London with the intention of travelling to Ibiza. The SFO said that more than 1,000 domestic and overseas investors had put money into the business or bought up flats or office space, and were promised returns of between 8% and 15%. However, in April 2020 one of its biggest subsidiaries, Signature Living Hotel Ltd, entered administration owing £113m, with other subsidiaries following suit. The SFO said it had found people “up and down the country” who were left out of pocket, while buildings in city centres had been left derelict. About 50 SFO staff were present at the dawn raids, alongside 20 officers from the National Crime Agency. The Guardian understands that one of the homes was in Greater Manchester and the other two were in Merseyside. The SFO said that it would not be confirming the identities of any individuals arrested. The company had more than 20 developments, including the Shankly and Dixie Dean football-themed hotels in Liverpool and the George Best Hotel in Belfast, which never opened. Kenwright said to staff in 2020 that the unprecedented financial situation the company found itself in had been “caused by the difficulties that the hospitality sector faces as a consequence of the Covid-19 pandemic”. Nick Ephgrave, the director of the SFO, said: “The scheme offered attractive returns and used much-loved local landmarks to lure investors. Today’s arrests and searches will help us reconstruct exactly what happened. This is now an active criminal investigation.” This is the fourth investigation started by the SFO since Ephgrave joined the agency in September with a pledge to increase the number and speed of inquiries. In a speech at the Royal United Services Institute (RUSI) in London last week, he said the SFO would be “bolder, more pragmatic, more proactive” under his leadership.