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.

Mr Shirawi was detained earlier this month on allegations of embezzlement relating to a deal carried out before he stepped down from Tamweel in January, said a lawyer close to the case. The lawyer said the case against Mr Shirawi appeared weak, relating to a transaction on a plot of land in a deal between Dubai Islamic Bank, Tamweel and another real estate company. Mr Shirawi remains on Tamweel’s board.

Istithmar, one of the vehicles set up by Sheikh Mohammed bin Rashid al-Maktoum, Dubai’s ruler, to channel some domestic savings abroad and diversify future income, issued a statement on Thursday “acknowledging reports” of the detention of Mr Shirawi and Feras Kalthoum, Istithmar’s chief financial officer, who is also a former Tamweel executive.

The fund, which has extensive holdings including New York retailer Barneys and stakes in Standard Chartered Bank and hedge fund GMG Partners, added that Istithmar was not subject to an investigation.

The Dubai probe has widened from DIB and Deyaar, its real estate unit, to include state-controlled companies such as Nakheel, the property giant responsible for Dubai’s offshore reclaimed island projects.

Nakheel earlier this week said it regularly made staff audits to “ensure transparency and regulation of procedure”.

The broadening investigation has created a tense atmosphere at Nakheel and several other state-owned companies, say employees. “I’ve never seen an investigation reach so far and so high,” said a senior Dubai official.

A few current and former executives from DIB and Deyaar have been detained in the inquiry. They include two Britons who had business dealings with DIB and a senior executive at JPMorgan’s Dubai office who used to work for DIB.

DIB has a 20 per cent stake in Tamweel, while Istithmar World holds a 22 per cent stake in the Sharia-compliant home finance company.

Tamweel’s share price fell 5.7 per cent on Thursday on news of Mr Shirawi’s detention but the company said it had received “no formal notification” of the investigation.