Two Transport Malta officials arrested on Monday in a bribery investigation were questioned and released by the police yesterday but another remains under arrest.

Field officer Joe Portelli and architect Daniel Cordina, a manager at the directorate, were both released.

Mr Cordina’s assistant, Gordon Zammit, was held for further questioning.

Transport Malta said last night that it decided to lift the suspension of Mr Portelli and Mr Cordina.

Police sources said the economic crimes unit and the criminal investigations department had been working on the case for more than a year.

Sources said that the case involved more than 20 roadwork contracts in various localities, valued at thousands of euros.

The three Transport Malta officials were arrested when the police raided their offices at about midday on Monday.

The transport watchdog then issued a brief statement saying that an inquiry was under way and the employees were being ­suspended pending the ­outcome.

Contacted yesterday, a Transport Malta spokesman refused to say whether the regulator had prompted the investigation or whether the allegations were made by third parties.

The spokesman said The Times should speak to the police on the investigations proper. Transport Malta did say however that such investigations were always a matter of concern and given due attention, adding, that given its wide remit, it was “understandable” that its very exposed to allegations.

Asked whether there had been an internal audit of Transport Malta’s checks and balances to prevent abuse in light of recent investigations, the spokesman said: “There are continuous updates to processes and procedures and there is also a rigorous internal audit function that reviews operations, where deemed fit.”

Transport Malta was involved in a police investigation in June 2010 into alleged bribery at the licensing and testing office.