An Italian judge is expected to decide on December 20 whether to send two oil majors, Eni and Shell, to trial over alleged corruption in Nigeria, two legal sources said on Tuesday.

Reuters reported that Milan prosecutors had asked for the two companies and some past and present managers, including the current Chief Executive Officer, Eni, Claudio Descalzi, to be indicted in a case revolving around the purchase of a Nigerian oilfield in 2011.

A judge must now rule whether to press charges or dismiss the case.

The Italian inquiry is one of several under way into the acquisition of the Oil Prospecting Licence 245 field for about $1.3bn, including current cases in the Netherlands and Nigeria.

Under Italian law, a company can be held responsible if it is deemed to have failed to prevent, or attempt to prevent a crime by an employee that benefitted the company.

On Tuesday, a court in Milan decided to wrap a strand of the investigation involving three former Shell managers and the current Shell Foundation Chairman, Malcolm Brinded, into the main inquiry, the sources said.

All the parties involved have denied any wrongdoing.

Last week, the Attorney General of the Federation and Minister of Justice, Mr. Abubakar Malami, said the sum of $85m had been recovered from the controversial $1.6bn Malabu deal from the United Kingdom.

Courts in Nigeria and Italy are investigating the purchase of the block by Shell and Eni. Shell said in April that it knew that some of the payments it made to Nigeria for the rights to the oil field would go to Malabu Oil and Gas, a company associated with a former Minister of Petroleum Resources and convicted money launderer, Dan Etete

Eni has said neither the company nor Descalzi were involved in any allegedly illicit conduct.

A Nigerian court ordered the asset temporarily seized in January at the request of the Economic and Financial Crimes Commission, but the move was overturned.

But a Federal High Court in Abuja in March discharged its interim forfeiture order on the controversial OPL 245.

The OPL 245, believed to be the largest in Africa, was said to have been fraudulently acquired from the Federal Government by Malabu Oil and Gas Limited in 1998.

The oil block, which was awarded by Etete to Malabu Oil and Gas, a company in which he was a shareholder, was sold to Shell and Eni in what has been described as a shady transaction.