Dubai has widened an anti-corruption investigation to include Adel Shirawi, vice-chairman of Istithmar World, one of the government’s investment funds, and a former chief executive of Tamweel, the home finance company.

The detention of such a senior official highlights efforts by the authorities to root out corruption in state-linked enterprises working in the emirate’s booming property sector. But while police have detained some suspects for five months, public prosecutors have yet to proceed to trial.